diff --git a/crates/squawk_ide/src/expand_selection.rs b/crates/squawk_ide/src/expand_selection.rs
index 0ed6dae3..193589c5 100644
--- a/crates/squawk_ide/src/expand_selection.rs
+++ b/crates/squawk_ide/src/expand_selection.rs
@@ -547,19 +547,18 @@ $0
             SyntaxKind::WHEN_CLAUSE_LIST,
         ];
 
-        let generated_list_kinds: Vec<SyntaxKind> = (0..SyntaxKind::__LAST as u16)
+        let unhandled_list_kinds = (0..SyntaxKind::__LAST as u16)
             .map(SyntaxKind::from)
             .filter(|kind| {
                 format!("{:?}", kind).ends_with("_LIST") && !delimited_ws_list_kinds.contains(kind)
             })
-            .collect();
-
-        let diff: Vec<SyntaxKind> = generated_list_kinds
-            .iter()
             .filter(|kind| !DELIMITED_LIST_KINDS.contains(kind))
-            .copied()
-            .collect();
+            .collect::<Vec<_>>();
 
-        assert_eq!(diff, vec![], "We shouldn't have any unhandled list kinds")
+        assert_eq!(
+            unhandled_list_kinds,
+            vec![],
+            "We shouldn't have any unhandled list kinds"
+        )
     }
 }
diff --git a/crates/squawk_parser/src/generated/syntax_kind.rs b/crates/squawk_parser/src/generated/syntax_kind.rs
index 0fc416a7..006e0d6e 100644
--- a/crates/squawk_parser/src/generated/syntax_kind.rs
+++ b/crates/squawk_parser/src/generated/syntax_kind.rs
@@ -845,6 +845,13 @@ pub enum SyntaxKind {
     MATCH_SIMPLE,
     MATERIALIZED,
     MERGE,
+    MERGE_DELETE,
+    MERGE_DO_NOTHING,
+    MERGE_INSERT,
+    MERGE_UPDATE,
+    MERGE_WHEN_MATCHED,
+    MERGE_WHEN_NOT_MATCHED_SOURCE,
+    MERGE_WHEN_NOT_MATCHED_TARGET,
     MOVE,
     NAME,
     NAMED_ARG,
diff --git a/crates/squawk_parser/src/grammar.rs b/crates/squawk_parser/src/grammar.rs
index 3f0ef022..1c3fd1bb 100644
--- a/crates/squawk_parser/src/grammar.rs
+++ b/crates/squawk_parser/src/grammar.rs
@@ -10261,22 +10261,35 @@ fn merge(p: &mut Parser<'_>, m: Option<Marker>) -> CompletedMarker {
 // and merge_delete is:
 // DELETE
 fn merge_when_clause(p: &mut Parser<'_>) {
+    let m = p.start();
     p.expect(WHEN_KW);
-    match p.current() {
+    let kind = match p.current() {
         MATCHED_KW => {
             p.bump(MATCHED_KW);
+            MERGE_WHEN_MATCHED
         }
         NOT_KW => {
             p.bump(NOT_KW);
             p.expect(MATCHED_KW);
-            // TODO: need a validation to check these
             // BY SOURCE | BY TARGET
             if p.eat(BY_KW) {
-                let _ = p.eat(SOURCE_KW) || p.eat(TARGET_KW);
+                if p.eat(SOURCE_KW) {
+                    MERGE_WHEN_NOT_MATCHED_SOURCE
+                } else if p.eat(TARGET_KW) {
+                    MERGE_WHEN_NOT_MATCHED_TARGET
+                } else {
+                    p.error("expected SOURCE or TARGET");
+                    MERGE_WHEN_NOT_MATCHED_TARGET
+                }
+            } else {
+                MERGE_WHEN_NOT_MATCHED_TARGET
             }
         }
-        _ => p.error("expected MATCHED, or NOT MATCHED"),
-    }
+        _ => {
+            p.error("expected MATCHED, or NOT MATCHED");
+            MERGE_WHEN_NOT_MATCHED_TARGET
+        }
+    };
     // [ AND condition ]
     if p.eat(AND_KW) {
         if expr(p).is_none() {
@@ -10284,16 +10297,24 @@ fn merge_when_clause(p: &mut Parser<'_>) {
         }
     }
     p.expect(THEN_KW);
-    // merge_update | merge_delete | merge_insert | DO NOTHING
-    match p.current() {
+    merge_action(p);
+    m.complete(p, kind);
+}
+
+// merge_update | merge_delete | merge_insert | DO NOTHING
+fn merge_action(p: &mut Parser<'_>) {
+    let m = p.start();
+    let kind = match p.current() {
         // merge_delete
         DELETE_KW => {
             p.bump(DELETE_KW);
+            MERGE_DELETE
         }
         // merge_update
         UPDATE_KW => {
             p.bump(UPDATE_KW);
             set_clause(p);
+            MERGE_UPDATE
         }
         // merge_insert
         INSERT_KW => {
@@ -10315,14 +10336,20 @@ fn merge_when_clause(p: &mut Parser<'_>) {
             } else {
                 p.error("expected VALUES or DEFAULT VALUES");
             }
+            MERGE_INSERT
         }
         // DO NOTHING
         DO_KW => {
             p.bump(DO_KW);
             p.expect(NOTHING_KW);
+            MERGE_DO_NOTHING
         }
-        _ => p.error("expected INSERT, UPDATE, DELETE, or DO NOTHING"),
-    }
+        _ => {
+            p.error("expected INSERT, UPDATE, DELETE, or DO NOTHING");
+            MERGE_DO_NOTHING
+        }
+    };
+    m.complete(p, kind);
 }
 
 // REASSIGN OWNED BY { old_role | CURRENT_ROLE | CURRENT_USER | SESSION_USER } [, ...]
diff --git a/crates/squawk_parser/tests/snapshots/tests__merge_ok.snap b/crates/squawk_parser/tests/snapshots/tests__merge_ok.snap
index 8d66a93a..ec227ccc 100644
--- a/crates/squawk_parser/tests/snapshots/tests__merge_ok.snap
+++ b/crates/squawk_parser/tests/snapshots/tests__merge_ok.snap
@@ -42,15 +42,17 @@ SOURCE_FILE
           NAME_REF
             IDENT "id"
     WHITESPACE "\n  "
-    WHEN_KW "when"
-    WHITESPACE " "
-    MATCHED_KW "matched"
-    WHITESPACE " "
-    THEN_KW "then"
-    WHITESPACE " \n    "
-    DO_KW "do"
-    WHITESPACE " "
-    NOTHING_KW "nothing"
+    MERGE_WHEN_MATCHED
+      WHEN_KW "when"
+      WHITESPACE " "
+      MATCHED_KW "matched"
+      WHITESPACE " "
+      THEN_KW "then"
+      WHITESPACE " \n    "
+      MERGE_DO_NOTHING
+        DO_KW "do"
+        WHITESPACE " "
+        NOTHING_KW "nothing"
   SEMICOLON ";"
   WHITESPACE "\n\n"
   COMMENT "-- aliases_with_as"
@@ -104,15 +106,17 @@ SOURCE_FILE
           NAME_REF
             IDENT "id"
     WHITESPACE "\n  "
-    WHEN_KW "when"
-    WHITESPACE " "
-    MATCHED_KW "matched"
-    WHITESPACE " "
-    THEN_KW "then"
-    WHITESPACE " \n    "
-    DO_KW "do"
-    WHITESPACE " "
-    NOTHING_KW "nothing"
+    MERGE_WHEN_MATCHED
+      WHEN_KW "when"
+      WHITESPACE " "
+      MATCHED_KW "matched"
+      WHITESPACE " "
+      THEN_KW "then"
+      WHITESPACE " \n    "
+      MERGE_DO_NOTHING
+        DO_KW "do"
+        WHITESPACE " "
+        NOTHING_KW "nothing"
   SEMICOLON ";"
   WHITESPACE "\n\n"
   COMMENT "-- using_rows_from"
@@ -156,15 +160,17 @@ SOURCE_FILE
       LITERAL
         TRUE_KW "true"
     WHITESPACE "\n  "
-    WHEN_KW "when"
-    WHITESPACE " "
-    MATCHED_KW "matched"
-    WHITESPACE " "
-    THEN_KW "then"
-    WHITESPACE " \n    "
-    DO_KW "do"
-    WHITESPACE " "
-    NOTHING_KW "nothing"
+    MERGE_WHEN_MATCHED
+      WHEN_KW "when"
+      WHITESPACE " "
+      MATCHED_KW "matched"
+      WHITESPACE " "
+      THEN_KW "then"
+      WHITESPACE " \n    "
+      MERGE_DO_NOTHING
+        DO_KW "do"
+        WHITESPACE " "
+        NOTHING_KW "nothing"
   SEMICOLON ";"
   WHITESPACE "\n\n"
   COMMENT "-- aliases_no_as"
@@ -214,15 +220,17 @@ SOURCE_FILE
           NAME_REF
             IDENT "id"
     WHITESPACE "\n  "
-    WHEN_KW "when"
-    WHITESPACE " "
-    MATCHED_KW "matched"
-    WHITESPACE " "
-    THEN_KW "then"
-    WHITESPACE " \n    "
-    DO_KW "do"
-    WHITESPACE " "
-    NOTHING_KW "nothing"
+    MERGE_WHEN_MATCHED
+      WHEN_KW "when"
+      WHITESPACE " "
+      MATCHED_KW "matched"
+      WHITESPACE " "
+      THEN_KW "then"
+      WHITESPACE " \n    "
+      MERGE_DO_NOTHING
+        DO_KW "do"
+        WHITESPACE " "
+        NOTHING_KW "nothing"
   SEMICOLON ";"
   WHITESPACE "\n\n"
   COMMENT "-- table_with_star"
@@ -266,15 +274,17 @@ SOURCE_FILE
           NAME_REF
             IDENT "id"
     WHITESPACE "\n  "
-    WHEN_KW "when"
-    WHITESPACE " "
-    MATCHED_KW "matched"
-    WHITESPACE " "
-    THEN_KW "then"
-    WHITESPACE " \n    "
-    DO_KW "do"
-    WHITESPACE " "
-    NOTHING_KW "nothing"
+    MERGE_WHEN_MATCHED
+      WHEN_KW "when"
+      WHITESPACE " "
+      MATCHED_KW "matched"
+      WHITESPACE " "
+      THEN_KW "then"
+      WHITESPACE " \n    "
+      MERGE_DO_NOTHING
+        DO_KW "do"
+        WHITESPACE " "
+        NOTHING_KW "nothing"
   SEMICOLON ";"
   WHITESPACE "\n\n"
   COMMENT "-- table_with_only"
@@ -318,15 +328,17 @@ SOURCE_FILE
           NAME_REF
             IDENT "id"
     WHITESPACE "\n  "
-    WHEN_KW "when"
-    WHITESPACE " "
-    MATCHED_KW "matched"
-    WHITESPACE " "
-    THEN_KW "then"
-    WHITESPACE " \n    "
-    DO_KW "do"
-    WHITESPACE " "
-    NOTHING_KW "nothing"
+    MERGE_WHEN_MATCHED
+      WHEN_KW "when"
+      WHITESPACE " "
+      MATCHED_KW "matched"
+      WHITESPACE " "
+      THEN_KW "then"
+      WHITESPACE " \n    "
+      MERGE_DO_NOTHING
+        DO_KW "do"
+        WHITESPACE " "
+        NOTHING_KW "nothing"
   SEMICOLON ";"
   WHITESPACE "\n\n"
   COMMENT "-- paren_query"
@@ -386,15 +398,17 @@ SOURCE_FILE
           NAME_REF
             IDENT "id"
     WHITESPACE "\n  "
-    WHEN_KW "when"
-    WHITESPACE " "
-    MATCHED_KW "matched"
-    WHITESPACE " "
-    THEN_KW "then"
-    WHITESPACE " \n    "
-    DO_KW "do"
-    WHITESPACE " "
-    NOTHING_KW "nothing"
+    MERGE_WHEN_MATCHED
+      WHEN_KW "when"
+      WHITESPACE " "
+      MATCHED_KW "matched"
+      WHITESPACE " "
+      THEN_KW "then"
+      WHITESPACE " \n    "
+      MERGE_DO_NOTHING
+        DO_KW "do"
+        WHITESPACE " "
+        NOTHING_KW "nothing"
   SEMICOLON ";"
   WHITESPACE "\n\n"
   MERGE
@@ -493,15 +507,17 @@ SOURCE_FILE
           NAME_REF
             IDENT "id"
     WHITESPACE "\n  "
-    WHEN_KW "when"
-    WHITESPACE " "
-    MATCHED_KW "matched"
-    WHITESPACE " "
-    THEN_KW "then"
-    WHITESPACE " \n    "
-    DO_KW "do"
-    WHITESPACE " "
-    NOTHING_KW "nothing"
+    MERGE_WHEN_MATCHED
+      WHEN_KW "when"
+      WHITESPACE " "
+      MATCHED_KW "matched"
+      WHITESPACE " "
+      THEN_KW "then"
+      WHITESPACE " \n    "
+      MERGE_DO_NOTHING
+        DO_KW "do"
+        WHITESPACE " "
+        NOTHING_KW "nothing"
   SEMICOLON ";"
   WHITESPACE "\n\n"
   MERGE
@@ -563,15 +579,17 @@ SOURCE_FILE
           NAME_REF
             IDENT "id"
     WHITESPACE "\n  "
-    WHEN_KW "when"
-    WHITESPACE " "
-    MATCHED_KW "matched"
-    WHITESPACE " "
-    THEN_KW "then"
-    WHITESPACE " \n    "
-    DO_KW "do"
-    WHITESPACE " "
-    NOTHING_KW "nothing"
+    MERGE_WHEN_MATCHED
+      WHEN_KW "when"
+      WHITESPACE " "
+      MATCHED_KW "matched"
+      WHITESPACE " "
+      THEN_KW "then"
+      WHITESPACE " \n    "
+      MERGE_DO_NOTHING
+        DO_KW "do"
+        WHITESPACE " "
+        NOTHING_KW "nothing"
   SEMICOLON ";"
   WHITESPACE "\n\n"
   COMMENT "-- when_clauses_dupe"
@@ -613,24 +631,28 @@ SOURCE_FILE
           NAME_REF
             IDENT "id"
     WHITESPACE "\n  "
-    WHEN_KW "when"
-    WHITESPACE " "
-    MATCHED_KW "matched"
-    WHITESPACE " "
-    THEN_KW "then"
-    WHITESPACE " \n    "
-    DO_KW "do"
-    WHITESPACE " "
-    NOTHING_KW "nothing"
+    MERGE_WHEN_MATCHED
+      WHEN_KW "when"
+      WHITESPACE " "
+      MATCHED_KW "matched"
+      WHITESPACE " "
+      THEN_KW "then"
+      WHITESPACE " \n    "
+      MERGE_DO_NOTHING
+        DO_KW "do"
+        WHITESPACE " "
+        NOTHING_KW "nothing"
     WHITESPACE "\n  "
-    WHEN_KW "when"
-    WHITESPACE " "
-    MATCHED_KW "matched"
-    WHITESPACE " "
-    THEN_KW "then"
-    WHITESPACE " \n    "
-    DO_KW "do"
-    WHITESPACE " "
-    NOTHING_KW "nothing"
+    MERGE_WHEN_MATCHED
+      WHEN_KW "when"
+      WHITESPACE " "
+      MATCHED_KW "matched"
+      WHITESPACE " "
+      THEN_KW "then"
+      WHITESPACE " \n    "
+      MERGE_DO_NOTHING
+        DO_KW "do"
+        WHITESPACE " "
+        NOTHING_KW "nothing"
   SEMICOLON ";"
   WHITESPACE "\n"
diff --git a/crates/squawk_parser/tests/snapshots/tests__merge_pg17_ok.snap b/crates/squawk_parser/tests/snapshots/tests__merge_pg17_ok.snap
index 81cd8d2e..c176dade 100644
--- a/crates/squawk_parser/tests/snapshots/tests__merge_pg17_ok.snap
+++ b/crates/squawk_parser/tests/snapshots/tests__merge_pg17_ok.snap
@@ -43,43 +43,49 @@ SOURCE_FILE
           NAME_REF
             IDENT "id"
     WHITESPACE "\n  "
-    WHEN_KW "when"
-    WHITESPACE " "
-    NOT_KW "not"
-    WHITESPACE " "
-    MATCHED_KW "matched"
-    WHITESPACE " "
-    THEN_KW "then"
-    WHITESPACE "\n    "
-    DO_KW "do"
-    WHITESPACE " "
-    NOTHING_KW "nothing"
+    MERGE_WHEN_NOT_MATCHED_TARGET
+      WHEN_KW "when"
+      WHITESPACE " "
+      NOT_KW "not"
+      WHITESPACE " "
+      MATCHED_KW "matched"
+      WHITESPACE " "
+      THEN_KW "then"
+      WHITESPACE "\n    "
+      MERGE_DO_NOTHING
+        DO_KW "do"
+        WHITESPACE " "
+        NOTHING_KW "nothing"
     WHITESPACE "\n  "
-    WHEN_KW "when"
-    WHITESPACE " "
-    MATCHED_KW "matched"
-    WHITESPACE " "
-    THEN_KW "then"
-    WHITESPACE " \n    "
-    DO_KW "do"
-    WHITESPACE " "
-    NOTHING_KW "nothing"
+    MERGE_WHEN_MATCHED
+      WHEN_KW "when"
+      WHITESPACE " "
+      MATCHED_KW "matched"
+      WHITESPACE " "
+      THEN_KW "then"
+      WHITESPACE " \n    "
+      MERGE_DO_NOTHING
+        DO_KW "do"
+        WHITESPACE " "
+        NOTHING_KW "nothing"
     WHITESPACE "\n  "
-    WHEN_KW "when"
-    WHITESPACE " "
-    NOT_KW "not"
-    WHITESPACE " "
-    MATCHED_KW "matched"
-    WHITESPACE " "
-    BY_KW "by"
-    WHITESPACE " "
-    SOURCE_KW "source"
-    WHITESPACE " "
-    THEN_KW "then"
-    WHITESPACE "\n    "
-    DO_KW "do"
-    WHITESPACE " "
-    NOTHING_KW "nothing"
+    MERGE_WHEN_NOT_MATCHED_SOURCE
+      WHEN_KW "when"
+      WHITESPACE " "
+      NOT_KW "not"
+      WHITESPACE " "
+      MATCHED_KW "matched"
+      WHITESPACE " "
+      BY_KW "by"
+      WHITESPACE " "
+      SOURCE_KW "source"
+      WHITESPACE " "
+      THEN_KW "then"
+      WHITESPACE "\n    "
+      MERGE_DO_NOTHING
+        DO_KW "do"
+        WHITESPACE " "
+        NOTHING_KW "nothing"
   SEMICOLON ";"
   WHITESPACE "\n\n"
   COMMENT "-- when_clauses_all_with_conditions"
@@ -107,76 +113,82 @@ SOURCE_FILE
       LITERAL
         TRUE_KW "true"
     WHITESPACE "\n  "
-    WHEN_KW "when"
-    WHITESPACE " "
-    MATCHED_KW "matched"
-    WHITESPACE " "
-    AND_KW "and"
-    WHITESPACE " "
-    BIN_EXPR
-      NAME_REF
-        IDENT "foo"
+    MERGE_WHEN_MATCHED
+      WHEN_KW "when"
       WHITESPACE " "
-      EQ "="
+      MATCHED_KW "matched"
       WHITESPACE " "
-      NAME_REF
-        IDENT "bar"
-    WHITESPACE " "
-    THEN_KW "then"
-    WHITESPACE "\n    "
-    DO_KW "do"
-    WHITESPACE " "
-    NOTHING_KW "nothing"
+      AND_KW "and"
+      WHITESPACE " "
+      BIN_EXPR
+        NAME_REF
+          IDENT "foo"
+        WHITESPACE " "
+        EQ "="
+        WHITESPACE " "
+        NAME_REF
+          IDENT "bar"
+      WHITESPACE " "
+      THEN_KW "then"
+      WHITESPACE "\n    "
+      MERGE_DO_NOTHING
+        DO_KW "do"
+        WHITESPACE " "
+        NOTHING_KW "nothing"
     WHITESPACE "\n  "
-    WHEN_KW "when"
-    WHITESPACE " "
-    NOT_KW "not"
-    WHITESPACE " "
-    MATCHED_KW "matched"
-    WHITESPACE " "
-    BY_KW "by"
-    WHITESPACE " "
-    SOURCE_KW "source"
-    WHITESPACE " "
-    AND_KW "and"
-    WHITESPACE " "
-    BIN_EXPR
-      NAME_REF
-        IDENT "bar"
+    MERGE_WHEN_NOT_MATCHED_SOURCE
+      WHEN_KW "when"
       WHITESPACE " "
-      EQ "="
+      NOT_KW "not"
       WHITESPACE " "
-      NAME_REF
-        IDENT "foo"
-    WHITESPACE " "
-    THEN_KW "then"
-    WHITESPACE "\n    "
-    DO_KW "do"
-    WHITESPACE " "
-    NOTHING_KW "nothing"
+      MATCHED_KW "matched"
+      WHITESPACE " "
+      BY_KW "by"
+      WHITESPACE " "
+      SOURCE_KW "source"
+      WHITESPACE " "
+      AND_KW "and"
+      WHITESPACE " "
+      BIN_EXPR
+        NAME_REF
+          IDENT "bar"
+        WHITESPACE " "
+        EQ "="
+        WHITESPACE " "
+        NAME_REF
+          IDENT "foo"
+      WHITESPACE " "
+      THEN_KW "then"
+      WHITESPACE "\n    "
+      MERGE_DO_NOTHING
+        DO_KW "do"
+        WHITESPACE " "
+        NOTHING_KW "nothing"
     WHITESPACE "\n  "
-    WHEN_KW "when"
-    WHITESPACE " "
-    NOT_KW "not"
-    WHITESPACE " "
-    MATCHED_KW "matched"
-    WHITESPACE " "
-    AND_KW "and"
-    WHITESPACE " "
-    BIN_EXPR
-      NAME_REF
-        IDENT "buzz"
+    MERGE_WHEN_NOT_MATCHED_TARGET
+      WHEN_KW "when"
       WHITESPACE " "
-      EQ "="
+      NOT_KW "not"
       WHITESPACE " "
-      NAME_REF
-        IDENT "bar"
-    WHITESPACE " "
-    THEN_KW "then"
-    WHITESPACE " \n    "
-    DO_KW "do"
-    WHITESPACE " "
-    NOTHING_KW "nothing"
+      MATCHED_KW "matched"
+      WHITESPACE " "
+      AND_KW "and"
+      WHITESPACE " "
+      BIN_EXPR
+        NAME_REF
+          IDENT "buzz"
+        WHITESPACE " "
+        EQ "="
+        WHITESPACE " "
+        NAME_REF
+          IDENT "bar"
+      WHITESPACE " "
+      THEN_KW "then"
+      WHITESPACE " \n    "
+      MERGE_DO_NOTHING
+        DO_KW "do"
+        WHITESPACE " "
+        NOTHING_KW "nothing"
   SEMICOLON ";"
   WHITESPACE "\n\n"
   COMMENT "-- returning_all"
@@ -218,43 +230,49 @@ SOURCE_FILE
           NAME_REF
             IDENT "id"
     WHITESPACE "\n  "
-    WHEN_KW "when"
-    WHITESPACE " "
-    NOT_KW "not"
-    WHITESPACE " "
-    MATCHED_KW "matched"
-    WHITESPACE " "
-    THEN_KW "then"
-    WHITESPACE "\n    "
-    DO_KW "do"
-    WHITESPACE " "
-    NOTHING_KW "nothing"
+    MERGE_WHEN_NOT_MATCHED_TARGET
+      WHEN_KW "when"
+      WHITESPACE " "
+      NOT_KW "not"
+      WHITESPACE " "
+      MATCHED_KW "matched"
+      WHITESPACE " "
+      THEN_KW "then"
+      WHITESPACE "\n    "
+      MERGE_DO_NOTHING
+        DO_KW "do"
+        WHITESPACE " "
+        NOTHING_KW "nothing"
     WHITESPACE "\n  "
-    WHEN_KW "when"
-    WHITESPACE " "
-    MATCHED_KW "matched"
-    WHITESPACE " "
-    THEN_KW "then"
-    WHITESPACE " \n    "
-    DO_KW "do"
-    WHITESPACE " "
-    NOTHING_KW "nothing"
+    MERGE_WHEN_MATCHED
+      WHEN_KW "when"
+      WHITESPACE " "
+      MATCHED_KW "matched"
+      WHITESPACE " "
+      THEN_KW "then"
+      WHITESPACE " \n    "
+      MERGE_DO_NOTHING
+        DO_KW "do"
+        WHITESPACE " "
+        NOTHING_KW "nothing"
     WHITESPACE "\n  "
-    WHEN_KW "when"
-    WHITESPACE " "
-    NOT_KW "not"
-    WHITESPACE " "
-    MATCHED_KW "matched"
-    WHITESPACE " "
-    BY_KW "by"
-    WHITESPACE " "
-    SOURCE_KW "source"
-    WHITESPACE " "
-    THEN_KW "then"
-    WHITESPACE "\n    "
-    DO_KW "do"
-    WHITESPACE " "
-    NOTHING_KW "nothing"
+    MERGE_WHEN_NOT_MATCHED_SOURCE
+      WHEN_KW "when"
+      WHITESPACE " "
+      NOT_KW "not"
+      WHITESPACE " "
+      MATCHED_KW "matched"
+      WHITESPACE " "
+      BY_KW "by"
+      WHITESPACE " "
+      SOURCE_KW "source"
+      WHITESPACE " "
+      THEN_KW "then"
+      WHITESPACE "\n    "
+      MERGE_DO_NOTHING
+        DO_KW "do"
+        WHITESPACE " "
+        NOTHING_KW "nothing"
     WHITESPACE "\n  "
     RETURNING_CLAUSE
       RETURNING_KW "returning"
@@ -303,43 +321,49 @@ SOURCE_FILE
           NAME_REF
             IDENT "id"
     WHITESPACE "\n  "
-    WHEN_KW "when"
-    WHITESPACE " "
-    NOT_KW "not"
-    WHITESPACE " "
-    MATCHED_KW "matched"
-    WHITESPACE " "
-    THEN_KW "then"
-    WHITESPACE "\n    "
-    DO_KW "do"
-    WHITESPACE " "
-    NOTHING_KW "nothing"
+    MERGE_WHEN_NOT_MATCHED_TARGET
+      WHEN_KW "when"
+      WHITESPACE " "
+      NOT_KW "not"
+      WHITESPACE " "
+      MATCHED_KW "matched"
+      WHITESPACE " "
+      THEN_KW "then"
+      WHITESPACE "\n    "
+      MERGE_DO_NOTHING
+        DO_KW "do"
+        WHITESPACE " "
+        NOTHING_KW "nothing"
     WHITESPACE "\n  "
-    WHEN_KW "when"
-    WHITESPACE " "
-    MATCHED_KW "matched"
-    WHITESPACE " "
-    THEN_KW "then"
-    WHITESPACE " \n    "
-    DO_KW "do"
-    WHITESPACE " "
-    NOTHING_KW "nothing"
+    MERGE_WHEN_MATCHED
+      WHEN_KW "when"
+      WHITESPACE " "
+      MATCHED_KW "matched"
+      WHITESPACE " "
+      THEN_KW "then"
+      WHITESPACE " \n    "
+      MERGE_DO_NOTHING
+        DO_KW "do"
+        WHITESPACE " "
+        NOTHING_KW "nothing"
     WHITESPACE "\n  "
-    WHEN_KW "when"
-    WHITESPACE " "
-    NOT_KW "not"
-    WHITESPACE " "
-    MATCHED_KW "matched"
-    WHITESPACE " "
-    BY_KW "by"
-    WHITESPACE " "
-    SOURCE_KW "source"
-    WHITESPACE " "
-    THEN_KW "then"
-    WHITESPACE "\n    "
-    DO_KW "do"
-    WHITESPACE " "
-    NOTHING_KW "nothing"
+    MERGE_WHEN_NOT_MATCHED_SOURCE
+      WHEN_KW "when"
+      WHITESPACE " "
+      NOT_KW "not"
+      WHITESPACE " "
+      MATCHED_KW "matched"
+      WHITESPACE " "
+      BY_KW "by"
+      WHITESPACE " "
+      SOURCE_KW "source"
+      WHITESPACE " "
+      THEN_KW "then"
+      WHITESPACE "\n    "
+      MERGE_DO_NOTHING
+        DO_KW "do"
+        WHITESPACE " "
+        NOTHING_KW "nothing"
     WHITESPACE "\n  "
     RETURNING_CLAUSE
       RETURNING_KW "returning"
@@ -423,19 +447,21 @@ SOURCE_FILE
           NAME_REF
             IDENT "id"
     WHITESPACE "\n  "
-    WHEN_KW "when"
-    WHITESPACE " "
-    NOT_KW "not"
-    WHITESPACE " "
-    MATCHED_KW "matched"
-    WHITESPACE " "
-    THEN_KW "then"
-    WHITESPACE "\n    "
-    INSERT_KW "insert"
-    WHITESPACE "\n    "
-    DEFAULT_KW "default"
-    WHITESPACE " "
-    VALUES_KW "values"
+    MERGE_WHEN_NOT_MATCHED_TARGET
+      WHEN_KW "when"
+      WHITESPACE " "
+      NOT_KW "not"
+      WHITESPACE " "
+      MATCHED_KW "matched"
+      WHITESPACE " "
+      THEN_KW "then"
+      WHITESPACE "\n    "
+      MERGE_INSERT
+        INSERT_KW "insert"
+        WHITESPACE "\n    "
+        DEFAULT_KW "default"
+        WHITESPACE " "
+        VALUES_KW "values"
   SEMICOLON ";"
   WHITESPACE "\n\n"
   COMMENT "-- merge_insert_default"
@@ -477,42 +503,44 @@ SOURCE_FILE
           NAME_REF
             IDENT "id"
     WHITESPACE "\n  "
-    WHEN_KW "when"
-    WHITESPACE " "
-    NOT_KW "not"
-    WHITESPACE " "
-    MATCHED_KW "matched"
-    WHITESPACE " "
-    THEN_KW "then"
-    WHITESPACE "\n    "
-    INSERT_KW "insert"
-    WHITESPACE " "
-    COLUMN_LIST
-      L_PAREN "("
-      COLUMN
-        NAME_REF
-          IDENT "a"
-      COMMA ","
+    MERGE_WHEN_NOT_MATCHED_TARGET
+      WHEN_KW "when"
       WHITESPACE " "
-      COLUMN
-        NAME_REF
-          IDENT "b"
-      COMMA ","
+      NOT_KW "not"
       WHITESPACE " "
-      COLUMN
-        NAME_REF
-          IDENT "c"
-      R_PAREN ")"
-    WHITESPACE "\n    "
-    OVERRIDING_KW "overriding"
-    WHITESPACE " "
-    USER_KW "user"
-    WHITESPACE " "
-    VALUE_KW "value"
-    WHITESPACE "\n    "
-    DEFAULT_KW "default"
-    WHITESPACE " "
-    VALUES_KW "values"
+      MATCHED_KW "matched"
+      WHITESPACE " "
+      THEN_KW "then"
+      WHITESPACE "\n    "
+      MERGE_INSERT
+        INSERT_KW "insert"
+        WHITESPACE " "
+        COLUMN_LIST
+          L_PAREN "("
+          COLUMN
+            NAME_REF
+              IDENT "a"
+          COMMA ","
+          WHITESPACE " "
+          COLUMN
+            NAME_REF
+              IDENT "b"
+          COMMA ","
+          WHITESPACE " "
+          COLUMN
+            NAME_REF
+              IDENT "c"
+          R_PAREN ")"
+        WHITESPACE "\n    "
+        OVERRIDING_KW "overriding"
+        WHITESPACE " "
+        USER_KW "user"
+        WHITESPACE " "
+        VALUE_KW "value"
+        WHITESPACE "\n    "
+        DEFAULT_KW "default"
+        WHITESPACE " "
+        VALUES_KW "values"
   SEMICOLON ";"
   WHITESPACE "\n\n"
   COMMENT "-- merge_insert_values"
@@ -554,59 +582,61 @@ SOURCE_FILE
           NAME_REF
             IDENT "id"
     WHITESPACE "\n  "
-    WHEN_KW "when"
-    WHITESPACE " "
-    NOT_KW "not"
-    WHITESPACE " "
-    MATCHED_KW "matched"
-    WHITESPACE " "
-    THEN_KW "then"
-    WHITESPACE "\n    "
-    INSERT_KW "insert"
-    WHITESPACE "\n    "
-    OVERRIDING_KW "overriding"
-    WHITESPACE " "
-    SYSTEM_KW "system"
-    WHITESPACE " "
-    VALUE_KW "value"
-    WHITESPACE "\n    "
-    VALUES
-      VALUES_KW "values"
+    MERGE_WHEN_NOT_MATCHED_TARGET
+      WHEN_KW "when"
       WHITESPACE " "
-      ROW_LIST
-        ROW
-          L_PAREN "("
-          LITERAL
-            INT_NUMBER "1"
-          COMMA ","
-          WHITESPACE " "
-          LITERAL
-            INT_NUMBER "2"
-          COMMA ","
-          WHITESPACE " "
-          LITERAL
-            DEFAULT_KW "default"
-          COMMA ","
-          WHITESPACE " "
-          LITERAL
-            INT_NUMBER "3"
-          COMMA ","
+      NOT_KW "not"
+      WHITESPACE " "
+      MATCHED_KW "matched"
+      WHITESPACE " "
+      THEN_KW "then"
+      WHITESPACE "\n    "
+      MERGE_INSERT
+        INSERT_KW "insert"
+        WHITESPACE "\n    "
+        OVERRIDING_KW "overriding"
+        WHITESPACE " "
+        SYSTEM_KW "system"
+        WHITESPACE " "
+        VALUE_KW "value"
+        WHITESPACE "\n    "
+        VALUES
+          VALUES_KW "values"
           WHITESPACE " "
-          BIN_EXPR
-            BIN_EXPR
+          ROW_LIST
+            ROW
+              L_PAREN "("
               LITERAL
-                INT_NUMBER "10"
+                INT_NUMBER "1"
+              COMMA ","
               WHITESPACE " "
-              STAR "*"
+              LITERAL
+                INT_NUMBER "2"
+              COMMA ","
               WHITESPACE " "
               LITERAL
-                INT_NUMBER "10"
-            WHITESPACE " "
-            PLUS "+"
-            WHITESPACE " "
-            LITERAL
-              INT_NUMBER "2"
-          R_PAREN ")"
+                DEFAULT_KW "default"
+              COMMA ","
+              WHITESPACE " "
+              LITERAL
+                INT_NUMBER "3"
+              COMMA ","
+              WHITESPACE " "
+              BIN_EXPR
+                BIN_EXPR
+                  LITERAL
+                    INT_NUMBER "10"
+                  WHITESPACE " "
+                  STAR "*"
+                  WHITESPACE " "
+                  LITERAL
+                    INT_NUMBER "10"
+                WHITESPACE " "
+                PLUS "+"
+                WHITESPACE " "
+                LITERAL
+                  INT_NUMBER "2"
+              R_PAREN ")"
   SEMICOLON ";"
   WHITESPACE "\n\n"
   COMMENT "-- merge_update"
@@ -648,137 +678,141 @@ SOURCE_FILE
           NAME_REF
             IDENT "id"
     WHITESPACE "\n  "
-    WHEN_KW "when"
-    WHITESPACE " "
-    MATCHED_KW "matched"
-    WHITESPACE " "
-    THEN_KW "then"
-    WHITESPACE "\n    "
-    UPDATE_KW "update"
-    WHITESPACE " "
-    SET_KW "set"
-    WHITESPACE "\n      "
-    NAME_REF
-      IDENT "a"
-    WHITESPACE " "
-    EQ "="
-    WHITESPACE " "
-    DEFAULT_KW "default"
-    COMMA ","
-    WHITESPACE "\n      "
-    NAME_REF
-      IDENT "b"
-    WHITESPACE " "
-    EQ "="
-    WHITESPACE " "
-    LITERAL
-      INT_NUMBER "1"
-    COMMA ","
-    WHITESPACE "\n      "
-    NAME_REF
-      IDENT "c"
-    WHITESPACE " "
-    EQ "="
-    WHITESPACE " "
-    NAME_REF
-      IDENT "d"
-    COMMA ","
-    WHITESPACE "\n      "
-    NAME_REF
-      IDENT "e"
-    WHITESPACE " "
-    EQ "="
-    WHITESPACE " "
-    PAREN_EXPR
-      L_PAREN "("
-      SELECT
-        SELECT_CLAUSE
-          SELECT_KW "select"
-          WHITESPACE " "
-          TARGET_LIST
-            TARGET
-              LITERAL
-                INT_NUMBER "1"
-      R_PAREN ")"
-    COMMA ","
-    WHITESPACE "\n      "
-    NAME_REF
-      IDENT "f"
-    WHITESPACE " "
-    EQ "="
-    WHITESPACE " "
-    CALL_EXPR
-      NAME_REF
-        ROW_KW "row"
-      ARG_LIST
-        L_PAREN "("
-        LITERAL
-          INT_NUMBER "1"
+    MERGE_WHEN_MATCHED
+      WHEN_KW "when"
+      WHITESPACE " "
+      MATCHED_KW "matched"
+      WHITESPACE " "
+      THEN_KW "then"
+      WHITESPACE "\n    "
+      MERGE_UPDATE
+        UPDATE_KW "update"
+        WHITESPACE " "
+        SET_KW "set"
+        WHITESPACE "\n      "
+        NAME_REF
+          IDENT "a"
+        WHITESPACE " "
+        EQ "="
+        WHITESPACE " "
+        DEFAULT_KW "default"
         COMMA ","
+        WHITESPACE "\n      "
+        NAME_REF
+          IDENT "b"
+        WHITESPACE " "
+        EQ "="
         WHITESPACE " "
         LITERAL
-          INT_NUMBER "2"
+          INT_NUMBER "1"
         COMMA ","
+        WHITESPACE "\n      "
+        NAME_REF
+          IDENT "c"
         WHITESPACE " "
-        LITERAL
-          DEFAULT_KW "default"
-        R_PAREN ")"
-    COMMA ","
-    WHITESPACE "\n      "
-    NAME_REF
-      IDENT "g"
-    WHITESPACE " "
-    EQ "="
-    WHITESPACE " "
-    TUPLE_EXPR
-      L_PAREN "("
-      LITERAL
-        INT_NUMBER "1"
-      COMMA ","
+        EQ "="
+        WHITESPACE " "
+        NAME_REF
+          IDENT "d"
+        COMMA ","
+        WHITESPACE "\n      "
+        NAME_REF
+          IDENT "e"
+        WHITESPACE " "
+        EQ "="
+        WHITESPACE " "
+        PAREN_EXPR
+          L_PAREN "("
+          SELECT
+            SELECT_CLAUSE
+              SELECT_KW "select"
+              WHITESPACE " "
+              TARGET_LIST
+                TARGET
+                  LITERAL
+                    INT_NUMBER "1"
+          R_PAREN ")"
+        COMMA ","
+        WHITESPACE "\n      "
+        NAME_REF
+          IDENT "f"
+        WHITESPACE " "
+        EQ "="
+        WHITESPACE " "
+        CALL_EXPR
+          NAME_REF
+            ROW_KW "row"
+          ARG_LIST
+            L_PAREN "("
+            LITERAL
+              INT_NUMBER "1"
+            COMMA ","
+            WHITESPACE " "
+            LITERAL
+              INT_NUMBER "2"
+            COMMA ","
+            WHITESPACE " "
+            LITERAL
+              DEFAULT_KW "default"
+            R_PAREN ")"
+        COMMA ","
+        WHITESPACE "\n      "
+        NAME_REF
+          IDENT "g"
+        WHITESPACE " "
+        EQ "="
+        WHITESPACE " "
+        TUPLE_EXPR
+          L_PAREN "("
+          LITERAL
+            INT_NUMBER "1"
+          COMMA ","
+          WHITESPACE " "
+          LITERAL
+            INT_NUMBER "2"
+          COMMA ","
+          WHITESPACE " "
+          LITERAL
+            DEFAULT_KW "default"
+          R_PAREN ")"
+        COMMA ","
+        WHITESPACE "\n      "
+        NAME_REF
+          IDENT "h"
+        WHITESPACE " "
+        EQ "="
+        WHITESPACE " "
+        PAREN_EXPR
+          L_PAREN "("
+          LITERAL
+            DEFAULT_KW "default"
+          R_PAREN ")"
+    WHITESPACE "\n  "
+    MERGE_WHEN_NOT_MATCHED_SOURCE
+      WHEN_KW "when"
       WHITESPACE " "
-      LITERAL
-        INT_NUMBER "2"
-      COMMA ","
+      NOT_KW "not"
       WHITESPACE " "
-      LITERAL
-        DEFAULT_KW "default"
-      R_PAREN ")"
-    COMMA ","
-    WHITESPACE "\n      "
-    NAME_REF
-      IDENT "h"
-    WHITESPACE " "
-    EQ "="
-    WHITESPACE " "
-    PAREN_EXPR
-      L_PAREN "("
-      LITERAL
-        DEFAULT_KW "default"
-      R_PAREN ")"
-    WHITESPACE "\n  "
-    WHEN_KW "when"
-    WHITESPACE " "
-    NOT_KW "not"
-    WHITESPACE " "
-    MATCHED_KW "matched"
-    WHITESPACE " "
-    BY_KW "by"
-    WHITESPACE " "
-    SOURCE_KW "source"
-    WHITESPACE " "
-    THEN_KW "then"
-    WHITESPACE "\n    "
-    UPDATE_KW "update"
-    WHITESPACE " "
-    SET_KW "set"
-    WHITESPACE " "
-    NAME_REF
-      IDENT "foo"
-    WHITESPACE " "
-    EQ "="
-    WHITESPACE " "
-    NAME_REF
-      IDENT "bar"
+      MATCHED_KW "matched"
+      WHITESPACE " "
+      BY_KW "by"
+      WHITESPACE " "
+      SOURCE_KW "source"
+      WHITESPACE " "
+      THEN_KW "then"
+      WHITESPACE "\n    "
+      MERGE_UPDATE
+        UPDATE_KW "update"
+        WHITESPACE " "
+        SET_KW "set"
+        WHITESPACE " "
+        NAME_REF
+          IDENT "foo"
+        WHITESPACE " "
+        EQ "="
+        WHITESPACE " "
+        NAME_REF
+          IDENT "bar"
   SEMICOLON ";"
   WHITESPACE "\n\n"
   COMMENT "-- merge_delete"
@@ -820,27 +854,31 @@ SOURCE_FILE
           NAME_REF
             IDENT "id"
     WHITESPACE "\n  "
-    WHEN_KW "when"
-    WHITESPACE " "
-    MATCHED_KW "matched"
-    WHITESPACE " "
-    THEN_KW "then"
-    WHITESPACE "\n    "
-    DELETE_KW "delete"
+    MERGE_WHEN_MATCHED
+      WHEN_KW "when"
+      WHITESPACE " "
+      MATCHED_KW "matched"
+      WHITESPACE " "
+      THEN_KW "then"
+      WHITESPACE "\n    "
+      MERGE_DELETE
+        DELETE_KW "delete"
     WHITESPACE "\n  "
-    WHEN_KW "when"
-    WHITESPACE " "
-    NOT_KW "not"
-    WHITESPACE " "
-    MATCHED_KW "matched"
-    WHITESPACE " "
-    BY_KW "by"
-    WHITESPACE " "
-    SOURCE_KW "source"
-    WHITESPACE " "
-    THEN_KW "then"
-    WHITESPACE "\n    "
-    DELETE_KW "delete"
+    MERGE_WHEN_NOT_MATCHED_SOURCE
+      WHEN_KW "when"
+      WHITESPACE " "
+      NOT_KW "not"
+      WHITESPACE " "
+      MATCHED_KW "matched"
+      WHITESPACE " "
+      BY_KW "by"
+      WHITESPACE " "
+      SOURCE_KW "source"
+      WHITESPACE " "
+      THEN_KW "then"
+      WHITESPACE "\n    "
+      MERGE_DELETE
+        DELETE_KW "delete"
   SEMICOLON ";"
   WHITESPACE "\n\n"
   COMMENT "-- with_select"
@@ -912,15 +950,17 @@ SOURCE_FILE
           NAME_REF
             IDENT "id"
     WHITESPACE "\n  "
-    WHEN_KW "when"
-    WHITESPACE " "
-    MATCHED_KW "matched"
-    WHITESPACE " "
-    THEN_KW "then"
-    WHITESPACE "\n    "
-    DO_KW "do"
-    WHITESPACE " "
-    NOTHING_KW "nothing"
+    MERGE_WHEN_MATCHED
+      WHEN_KW "when"
+      WHITESPACE " "
+      MATCHED_KW "matched"
+      WHITESPACE " "
+      THEN_KW "then"
+      WHITESPACE "\n    "
+      MERGE_DO_NOTHING
+        DO_KW "do"
+        WHITESPACE " "
+        NOTHING_KW "nothing"
   SEMICOLON ";"
   WHITESPACE "\n\n"
   COMMENT "-- doc_example_1"
@@ -970,73 +1010,77 @@ SOURCE_FILE
           NAME_REF
             IDENT "customer_id"
     WHITESPACE "\n"
-    WHEN_KW "WHEN"
-    WHITESPACE " "
-    MATCHED_KW "MATCHED"
-    WHITESPACE " "
-    THEN_KW "THEN"
-    WHITESPACE "\n  "
-    UPDATE_KW "UPDATE"
-    WHITESPACE " "
-    SET_KW "SET"
-    WHITESPACE " "
-    NAME_REF
-      IDENT "balance"
-    WHITESPACE " "
-    EQ "="
-    WHITESPACE " "
-    BIN_EXPR
-      NAME_REF
-        IDENT "balance"
+    MERGE_WHEN_MATCHED
+      WHEN_KW "WHEN"
       WHITESPACE " "
-      PLUS "+"
+      MATCHED_KW "MATCHED"
       WHITESPACE " "
-      NAME_REF
-        IDENT "transaction_value"
-    WHITESPACE "\n"
-    WHEN_KW "WHEN"
-    WHITESPACE " "
-    NOT_KW "NOT"
-    WHITESPACE " "
-    MATCHED_KW "MATCHED"
-    WHITESPACE " "
-    THEN_KW "THEN"
-    WHITESPACE "\n  "
-    INSERT_KW "INSERT"
-    WHITESPACE " "
-    COLUMN_LIST
-      L_PAREN "("
-      COLUMN
-        NAME_REF
-          IDENT "customer_id"
-      COMMA ","
-      WHITESPACE " "
-      COLUMN
+      THEN_KW "THEN"
+      WHITESPACE "\n  "
+      MERGE_UPDATE
+        UPDATE_KW "UPDATE"
+        WHITESPACE " "
+        SET_KW "SET"
+        WHITESPACE " "
         NAME_REF
           IDENT "balance"
-      R_PAREN ")"
-    WHITESPACE "\n  "
-    VALUES
-      VALUES_KW "VALUES"
+        WHITESPACE " "
+        EQ "="
+        WHITESPACE " "
+        BIN_EXPR
+          NAME_REF
+            IDENT "balance"
+          WHITESPACE " "
+          PLUS "+"
+          WHITESPACE " "
+          NAME_REF
+            IDENT "transaction_value"
+    WHITESPACE "\n"
+    MERGE_WHEN_NOT_MATCHED_TARGET
+      WHEN_KW "WHEN"
+      WHITESPACE " "
+      NOT_KW "NOT"
       WHITESPACE " "
-      ROW_LIST
-        ROW
+      MATCHED_KW "MATCHED"
+      WHITESPACE " "
+      THEN_KW "THEN"
+      WHITESPACE "\n  "
+      MERGE_INSERT
+        INSERT_KW "INSERT"
+        WHITESPACE " "
+        COLUMN_LIST
           L_PAREN "("
-          FIELD_EXPR
-            NAME_REF
-              IDENT "t"
-            DOT "."
+          COLUMN
             NAME_REF
               IDENT "customer_id"
           COMMA ","
           WHITESPACE " "
-          FIELD_EXPR
+          COLUMN
             NAME_REF
-              IDENT "t"
-            DOT "."
-            NAME_REF
-              IDENT "transaction_value"
+              IDENT "balance"
           R_PAREN ")"
+        WHITESPACE "\n  "
+        VALUES
+          VALUES_KW "VALUES"
+          WHITESPACE " "
+          ROW_LIST
+            ROW
+              L_PAREN "("
+              FIELD_EXPR
+                NAME_REF
+                  IDENT "t"
+                DOT "."
+                NAME_REF
+                  IDENT "customer_id"
+              COMMA ","
+              WHITESPACE " "
+              FIELD_EXPR
+                NAME_REF
+                  IDENT "t"
+                DOT "."
+                NAME_REF
+                  IDENT "transaction_value"
+              R_PAREN ")"
   SEMICOLON ";"
   WHITESPACE "\n\n"
   COMMENT "-- doc_example_2"
@@ -1109,73 +1153,77 @@ SOURCE_FILE
           NAME_REF
             IDENT "customer_id"
     WHITESPACE "\n"
-    WHEN_KW "WHEN"
-    WHITESPACE " "
-    MATCHED_KW "MATCHED"
-    WHITESPACE " "
-    THEN_KW "THEN"
-    WHITESPACE "\n  "
-    UPDATE_KW "UPDATE"
-    WHITESPACE " "
-    SET_KW "SET"
-    WHITESPACE " "
-    NAME_REF
-      IDENT "balance"
-    WHITESPACE " "
-    EQ "="
-    WHITESPACE " "
-    BIN_EXPR
-      NAME_REF
-        IDENT "balance"
-      WHITESPACE " "
-      PLUS "+"
+    MERGE_WHEN_MATCHED
+      WHEN_KW "WHEN"
       WHITESPACE " "
-      NAME_REF
-        IDENT "transaction_value"
-    WHITESPACE "\n"
-    WHEN_KW "WHEN"
-    WHITESPACE " "
-    NOT_KW "NOT"
-    WHITESPACE " "
-    MATCHED_KW "MATCHED"
-    WHITESPACE " "
-    THEN_KW "THEN"
-    WHITESPACE "\n  "
-    INSERT_KW "INSERT"
-    WHITESPACE " "
-    COLUMN_LIST
-      L_PAREN "("
-      COLUMN
-        NAME_REF
-          IDENT "customer_id"
-      COMMA ","
+      MATCHED_KW "MATCHED"
       WHITESPACE " "
-      COLUMN
+      THEN_KW "THEN"
+      WHITESPACE "\n  "
+      MERGE_UPDATE
+        UPDATE_KW "UPDATE"
+        WHITESPACE " "
+        SET_KW "SET"
+        WHITESPACE " "
         NAME_REF
           IDENT "balance"
-      R_PAREN ")"
-    WHITESPACE "\n  "
-    VALUES
-      VALUES_KW "VALUES"
+        WHITESPACE " "
+        EQ "="
+        WHITESPACE " "
+        BIN_EXPR
+          NAME_REF
+            IDENT "balance"
+          WHITESPACE " "
+          PLUS "+"
+          WHITESPACE " "
+          NAME_REF
+            IDENT "transaction_value"
+    WHITESPACE "\n"
+    MERGE_WHEN_NOT_MATCHED_TARGET
+      WHEN_KW "WHEN"
       WHITESPACE " "
-      ROW_LIST
-        ROW
+      NOT_KW "NOT"
+      WHITESPACE " "
+      MATCHED_KW "MATCHED"
+      WHITESPACE " "
+      THEN_KW "THEN"
+      WHITESPACE "\n  "
+      MERGE_INSERT
+        INSERT_KW "INSERT"
+        WHITESPACE " "
+        COLUMN_LIST
           L_PAREN "("
-          FIELD_EXPR
-            NAME_REF
-              IDENT "t"
-            DOT "."
+          COLUMN
             NAME_REF
               IDENT "customer_id"
           COMMA ","
           WHITESPACE " "
-          FIELD_EXPR
-            NAME_REF
-              IDENT "t"
-            DOT "."
+          COLUMN
             NAME_REF
-              IDENT "transaction_value"
+              IDENT "balance"
           R_PAREN ")"
+        WHITESPACE "\n  "
+        VALUES
+          VALUES_KW "VALUES"
+          WHITESPACE " "
+          ROW_LIST
+            ROW
+              L_PAREN "("
+              FIELD_EXPR
+                NAME_REF
+                  IDENT "t"
+                DOT "."
+                NAME_REF
+                  IDENT "customer_id"
+              COMMA ","
+              WHITESPACE " "
+              FIELD_EXPR
+                NAME_REF
+                  IDENT "t"
+                DOT "."
+                NAME_REF
+                  IDENT "transaction_value"
+              R_PAREN ")"
   SEMICOLON ";"
   WHITESPACE "\n\n"
   COMMENT "-- doc_example_3"
@@ -1225,43 +1273,71 @@ SOURCE_FILE
           NAME_REF
             IDENT "winename"
     WHITESPACE "\n"
-    WHEN_KW "WHEN"
-    WHITESPACE " "
-    NOT_KW "NOT"
-    WHITESPACE " "
-    MATCHED_KW "MATCHED"
-    WHITESPACE " "
-    AND_KW "AND"
-    WHITESPACE " "
-    BIN_EXPR
-      FIELD_EXPR
-        NAME_REF
-          IDENT "s"
-        DOT "."
-        NAME_REF
-          IDENT "stock_delta"
+    MERGE_WHEN_NOT_MATCHED_TARGET
+      WHEN_KW "WHEN"
       WHITESPACE " "
-      R_ANGLE ">"
+      NOT_KW "NOT"
       WHITESPACE " "
-      LITERAL
-        INT_NUMBER "0"
-    WHITESPACE " "
-    THEN_KW "THEN"
-    WHITESPACE "\n  "
-    INSERT_KW "INSERT"
-    WHITESPACE " "
-    VALUES
-      VALUES_KW "VALUES"
-      ROW_LIST
-        ROW
-          L_PAREN "("
+      MATCHED_KW "MATCHED"
+      WHITESPACE " "
+      AND_KW "AND"
+      WHITESPACE " "
+      BIN_EXPR
+        FIELD_EXPR
+          NAME_REF
+            IDENT "s"
+          DOT "."
+          NAME_REF
+            IDENT "stock_delta"
+        WHITESPACE " "
+        R_ANGLE ">"
+        WHITESPACE " "
+        LITERAL
+          INT_NUMBER "0"
+      WHITESPACE " "
+      THEN_KW "THEN"
+      WHITESPACE "\n  "
+      MERGE_INSERT
+        INSERT_KW "INSERT"
+        WHITESPACE " "
+        VALUES
+          VALUES_KW "VALUES"
+          ROW_LIST
+            ROW
+              L_PAREN "("
+              FIELD_EXPR
+                NAME_REF
+                  IDENT "s"
+                DOT "."
+                NAME_REF
+                  IDENT "winename"
+              COMMA ","
+              WHITESPACE " "
+              FIELD_EXPR
+                NAME_REF
+                  IDENT "s"
+                DOT "."
+                NAME_REF
+                  IDENT "stock_delta"
+              R_PAREN ")"
+    WHITESPACE "\n"
+    MERGE_WHEN_MATCHED
+      WHEN_KW "WHEN"
+      WHITESPACE " "
+      MATCHED_KW "MATCHED"
+      WHITESPACE " "
+      AND_KW "AND"
+      WHITESPACE " "
+      BIN_EXPR
+        BIN_EXPR
           FIELD_EXPR
             NAME_REF
-              IDENT "s"
+              IDENT "w"
             DOT "."
             NAME_REF
-              IDENT "winename"
-          COMMA ","
+              IDENT "stock"
+          WHITESPACE " "
+          PLUS "+"
           WHITESPACE " "
           FIELD_EXPR
             NAME_REF
@@ -1269,72 +1345,50 @@ SOURCE_FILE
             DOT "."
             NAME_REF
               IDENT "stock_delta"
-          R_PAREN ")"
-    WHITESPACE "\n"
-    WHEN_KW "WHEN"
-    WHITESPACE " "
-    MATCHED_KW "MATCHED"
-    WHITESPACE " "
-    AND_KW "AND"
-    WHITESPACE " "
-    BIN_EXPR
-      BIN_EXPR
-        FIELD_EXPR
-          NAME_REF
-            IDENT "w"
-          DOT "."
-          NAME_REF
-            IDENT "stock"
         WHITESPACE " "
-        PLUS "+"
+        R_ANGLE ">"
         WHITESPACE " "
-        FIELD_EXPR
-          NAME_REF
-            IDENT "s"
-          DOT "."
-          NAME_REF
-            IDENT "stock_delta"
-      WHITESPACE " "
-      R_ANGLE ">"
+        LITERAL
+          INT_NUMBER "0"
       WHITESPACE " "
-      LITERAL
-        INT_NUMBER "0"
-    WHITESPACE " "
-    THEN_KW "THEN"
-    WHITESPACE "\n  "
-    UPDATE_KW "UPDATE"
-    WHITESPACE " "
-    SET_KW "SET"
-    WHITESPACE " "
-    NAME_REF
-      IDENT "stock"
-    WHITESPACE " "
-    EQ "="
-    WHITESPACE " "
-    BIN_EXPR
-      FIELD_EXPR
-        NAME_REF
-          IDENT "w"
-        DOT "."
+      THEN_KW "THEN"
+      WHITESPACE "\n  "
+      MERGE_UPDATE
+        UPDATE_KW "UPDATE"
+        WHITESPACE " "
+        SET_KW "SET"
+        WHITESPACE " "
         NAME_REF
           IDENT "stock"
+        WHITESPACE " "
+        EQ "="
+        WHITESPACE " "
+        BIN_EXPR
+          FIELD_EXPR
+            NAME_REF
+              IDENT "w"
+            DOT "."
+            NAME_REF
+              IDENT "stock"
+          WHITESPACE " "
+          PLUS "+"
+          WHITESPACE " "
+          FIELD_EXPR
+            NAME_REF
+              IDENT "s"
+            DOT "."
+            NAME_REF
+              IDENT "stock_delta"
+    WHITESPACE "\n"
+    MERGE_WHEN_MATCHED
+      WHEN_KW "WHEN"
       WHITESPACE " "
-      PLUS "+"
+      MATCHED_KW "MATCHED"
       WHITESPACE " "
-      FIELD_EXPR
-        NAME_REF
-          IDENT "s"
-        DOT "."
-        NAME_REF
-          IDENT "stock_delta"
-    WHITESPACE "\n"
-    WHEN_KW "WHEN"
-    WHITESPACE " "
-    MATCHED_KW "MATCHED"
-    WHITESPACE " "
-    THEN_KW "THEN"
-    WHITESPACE "\n  "
-    DELETE_KW "DELETE"
+      THEN_KW "THEN"
+      WHITESPACE "\n  "
+      MERGE_DELETE
+        DELETE_KW "DELETE"
     WHITESPACE "\n"
     RETURNING_CLAUSE
       RETURNING_KW "RETURNING"
@@ -1404,94 +1458,100 @@ SOURCE_FILE
           NAME_REF
             IDENT "winename"
     WHITESPACE "\n"
-    WHEN_KW "WHEN"
-    WHITESPACE " "
-    NOT_KW "NOT"
-    WHITESPACE " "
-    MATCHED_KW "MATCHED"
-    WHITESPACE " "
-    BY_KW "BY"
-    WHITESPACE " "
-    TARGET_KW "TARGET"
-    WHITESPACE " "
-    THEN_KW "THEN"
-    WHITESPACE "\n  "
-    INSERT_KW "INSERT"
-    WHITESPACE " "
-    VALUES
-      VALUES_KW "VALUES"
-      ROW_LIST
-        ROW
-          L_PAREN "("
-          FIELD_EXPR
-            NAME_REF
-              IDENT "s"
-            DOT "."
-            NAME_REF
-              IDENT "winename"
-          COMMA ","
-          WHITESPACE " "
-          FIELD_EXPR
-            NAME_REF
-              IDENT "s"
-            DOT "."
-            NAME_REF
-              IDENT "stock"
-          R_PAREN ")"
+    MERGE_WHEN_NOT_MATCHED_TARGET
+      WHEN_KW "WHEN"
+      WHITESPACE " "
+      NOT_KW "NOT"
+      WHITESPACE " "
+      MATCHED_KW "MATCHED"
+      WHITESPACE " "
+      BY_KW "BY"
+      WHITESPACE " "
+      TARGET_KW "TARGET"
+      WHITESPACE " "
+      THEN_KW "THEN"
+      WHITESPACE "\n  "
+      MERGE_INSERT
+        INSERT_KW "INSERT"
+        WHITESPACE " "
+        VALUES
+          VALUES_KW "VALUES"
+          ROW_LIST
+            ROW
+              L_PAREN "("
+              FIELD_EXPR
+                NAME_REF
+                  IDENT "s"
+                DOT "."
+                NAME_REF
+                  IDENT "winename"
+              COMMA ","
+              WHITESPACE " "
+              FIELD_EXPR
+                NAME_REF
+                  IDENT "s"
+                DOT "."
+                NAME_REF
+                  IDENT "stock"
+              R_PAREN ")"
     WHITESPACE "\n"
-    WHEN_KW "WHEN"
-    WHITESPACE " "
-    MATCHED_KW "MATCHED"
-    WHITESPACE " "
-    AND_KW "AND"
-    WHITESPACE " "
-    BIN_EXPR
-      FIELD_EXPR
-        NAME_REF
-          IDENT "w"
-        DOT "."
-        NAME_REF
-          IDENT "stock"
+    MERGE_WHEN_MATCHED
+      WHEN_KW "WHEN"
       WHITESPACE " "
-      NEQ "!="
+      MATCHED_KW "MATCHED"
       WHITESPACE " "
-      FIELD_EXPR
-        NAME_REF
-          IDENT "s"
-        DOT "."
+      AND_KW "AND"
+      WHITESPACE " "
+      BIN_EXPR
+        FIELD_EXPR
+          NAME_REF
+            IDENT "w"
+          DOT "."
+          NAME_REF
+            IDENT "stock"
+        WHITESPACE " "
+        NEQ "!="
+        WHITESPACE " "
+        FIELD_EXPR
+          NAME_REF
+            IDENT "s"
+          DOT "."
+          NAME_REF
+            IDENT "stock"
+      WHITESPACE " "
+      THEN_KW "THEN"
+      WHITESPACE "\n  "
+      MERGE_UPDATE
+        UPDATE_KW "UPDATE"
+        WHITESPACE " "
+        SET_KW "SET"
+        WHITESPACE " "
         NAME_REF
           IDENT "stock"
-    WHITESPACE " "
-    THEN_KW "THEN"
-    WHITESPACE "\n  "
-    UPDATE_KW "UPDATE"
-    WHITESPACE " "
-    SET_KW "SET"
-    WHITESPACE " "
-    NAME_REF
-      IDENT "stock"
-    WHITESPACE " "
-    EQ "="
-    WHITESPACE " "
-    FIELD_EXPR
-      NAME_REF
-        IDENT "s"
-      DOT "."
-      NAME_REF
-        IDENT "stock"
+        WHITESPACE " "
+        EQ "="
+        WHITESPACE " "
+        FIELD_EXPR
+          NAME_REF
+            IDENT "s"
+          DOT "."
+          NAME_REF
+            IDENT "stock"
     WHITESPACE "\n"
-    WHEN_KW "WHEN"
-    WHITESPACE " "
-    NOT_KW "NOT"
-    WHITESPACE " "
-    MATCHED_KW "MATCHED"
-    WHITESPACE " "
-    BY_KW "BY"
-    WHITESPACE " "
-    SOURCE_KW "SOURCE"
-    WHITESPACE " "
-    THEN_KW "THEN"
-    WHITESPACE "\n  "
-    DELETE_KW "DELETE"
+    MERGE_WHEN_NOT_MATCHED_SOURCE
+      WHEN_KW "WHEN"
+      WHITESPACE " "
+      NOT_KW "NOT"
+      WHITESPACE " "
+      MATCHED_KW "MATCHED"
+      WHITESPACE " "
+      BY_KW "BY"
+      WHITESPACE " "
+      SOURCE_KW "SOURCE"
+      WHITESPACE " "
+      THEN_KW "THEN"
+      WHITESPACE "\n  "
+      MERGE_DELETE
+        DELETE_KW "DELETE"
   SEMICOLON ";"
   WHITESPACE "\n"
diff --git a/crates/squawk_parser/tests/snapshots/tests__prepare_ok.snap b/crates/squawk_parser/tests/snapshots/tests__prepare_ok.snap
index 99076920..45651131 100644
--- a/crates/squawk_parser/tests/snapshots/tests__prepare_ok.snap
+++ b/crates/squawk_parser/tests/snapshots/tests__prepare_ok.snap
@@ -336,43 +336,49 @@ SOURCE_FILE
             NAME_REF
               IDENT "id"
       WHITESPACE "\n  "
-      WHEN_KW "when"
-      WHITESPACE " "
-      MATCHED_KW "matched"
-      WHITESPACE " "
-      THEN_KW "then"
-      WHITESPACE " "
-      DO_KW "do"
-      WHITESPACE " "
-      NOTHING_KW "nothing"
+      MERGE_WHEN_MATCHED
+        WHEN_KW "when"
+        WHITESPACE " "
+        MATCHED_KW "matched"
+        WHITESPACE " "
+        THEN_KW "then"
+        WHITESPACE " "
+        MERGE_DO_NOTHING
+          DO_KW "do"
+          WHITESPACE " "
+          NOTHING_KW "nothing"
       WHITESPACE "\n  "
-      WHEN_KW "when"
-      WHITESPACE " "
-      NOT_KW "not"
-      WHITESPACE " "
-      MATCHED_KW "matched"
-      WHITESPACE " "
-      BY_KW "by"
-      WHITESPACE " "
-      SOURCE_KW "source"
-      WHITESPACE " "
-      THEN_KW "then"
-      WHITESPACE " "
-      DO_KW "do"
-      WHITESPACE " "
-      NOTHING_KW "nothing"
+      MERGE_WHEN_NOT_MATCHED_SOURCE
+        WHEN_KW "when"
+        WHITESPACE " "
+        NOT_KW "not"
+        WHITESPACE " "
+        MATCHED_KW "matched"
+        WHITESPACE " "
+        BY_KW "by"
+        WHITESPACE " "
+        SOURCE_KW "source"
+        WHITESPACE " "
+        THEN_KW "then"
+        WHITESPACE " "
+        MERGE_DO_NOTHING
+          DO_KW "do"
+          WHITESPACE " "
+          NOTHING_KW "nothing"
       WHITESPACE "\n  "
-      WHEN_KW "when"
-      WHITESPACE " "
-      NOT_KW "not"
-      WHITESPACE " "
-      MATCHED_KW "matched"
-      WHITESPACE " "
-      THEN_KW "then"
-      WHITESPACE " "
-      DO_KW "do"
-      WHITESPACE " "
-      NOTHING_KW "nothing"
+      MERGE_WHEN_NOT_MATCHED_TARGET
+        WHEN_KW "when"
+        WHITESPACE " "
+        NOT_KW "not"
+        WHITESPACE " "
+        MATCHED_KW "matched"
+        WHITESPACE " "
+        THEN_KW "then"
+        WHITESPACE " "
+        MERGE_DO_NOTHING
+          DO_KW "do"
+          WHITESPACE " "
+          NOTHING_KW "nothing"
   SEMICOLON ";"
   WHITESPACE "\n\n"
   COMMENT "-- values"
diff --git a/crates/squawk_parser/tests/snapshots/tests__select_cte_ok.snap b/crates/squawk_parser/tests/snapshots/tests__select_cte_ok.snap
index 1e5e0fd6..a96fc3b7 100644
--- a/crates/squawk_parser/tests/snapshots/tests__select_cte_ok.snap
+++ b/crates/squawk_parser/tests/snapshots/tests__select_cte_ok.snap
@@ -40,15 +40,17 @@ SOURCE_FILE
             LITERAL
               TRUE_KW "true"
           WHITESPACE "\n    "
-          WHEN_KW "when"
-          WHITESPACE " "
-          MATCHED_KW "matched"
-          WHITESPACE " "
-          THEN_KW "then"
-          WHITESPACE " \n      "
-          DO_KW "do"
-          WHITESPACE " "
-          NOTHING_KW "nothing"
+          MERGE_WHEN_MATCHED
+            WHEN_KW "when"
+            WHITESPACE " "
+            MATCHED_KW "matched"
+            WHITESPACE " "
+            THEN_KW "then"
+            WHITESPACE " \n      "
+            MERGE_DO_NOTHING
+              DO_KW "do"
+              WHITESPACE " "
+              NOTHING_KW "nothing"
         WHITESPACE "\n"
         R_PAREN ")"
     WHITESPACE "\n"
diff --git a/crates/squawk_syntax/src/ast/generated/nodes.rs b/crates/squawk_syntax/src/ast/generated/nodes.rs
index 5e987ed0..a175d530 100644
--- a/crates/squawk_syntax/src/ast/generated/nodes.rs
+++ b/crates/squawk_syntax/src/ast/generated/nodes.rs
@@ -6461,10 +6461,207 @@ pub struct Merge {
     pub(crate) syntax: SyntaxNode,
 }
 impl Merge {
+    #[inline]
+    pub fn alias(&self) -> Option<Alias> {
+        support::child(&self.syntax)
+    }
+    #[inline]
+    pub fn merge_when_clauses(&self) -> AstChildren<MergeWhenClause> {
+        support::children(&self.syntax)
+    }
+    #[inline]
+    pub fn name_ref(&self) -> Option<NameRef> {
+        support::child(&self.syntax)
+    }
+    #[inline]
+    pub fn using_clause(&self) -> Option<UsingClause> {
+        support::child(&self.syntax)
+    }
+    #[inline]
+    pub fn star_token(&self) -> Option<SyntaxToken> {
+        support::token(&self.syntax, SyntaxKind::STAR)
+    }
+    #[inline]
+    pub fn into_token(&self) -> Option<SyntaxToken> {
+        support::token(&self.syntax, SyntaxKind::INTO_KW)
+    }
     #[inline]
     pub fn merge_token(&self) -> Option<SyntaxToken> {
         support::token(&self.syntax, SyntaxKind::MERGE_KW)
     }
+    #[inline]
+    pub fn only_token(&self) -> Option<SyntaxToken> {
+        support::token(&self.syntax, SyntaxKind::ONLY_KW)
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct MergeDelete {
+    pub(crate) syntax: SyntaxNode,
+}
+impl MergeDelete {
+    #[inline]
+    pub fn delete_token(&self) -> Option<SyntaxToken> {
+        support::token(&self.syntax, SyntaxKind::DELETE_KW)
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct MergeDoNothing {
+    pub(crate) syntax: SyntaxNode,
+}
+impl MergeDoNothing {
+    #[inline]
+    pub fn do_token(&self) -> Option<SyntaxToken> {
+        support::token(&self.syntax, SyntaxKind::DO_KW)
+    }
+    #[inline]
+    pub fn nothing_token(&self) -> Option<SyntaxToken> {
+        support::token(&self.syntax, SyntaxKind::NOTHING_KW)
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct MergeInsert {
+    pub(crate) syntax: SyntaxNode,
+}
+impl MergeInsert {
+    #[inline]
+    pub fn insert_token(&self) -> Option<SyntaxToken> {
+        support::token(&self.syntax, SyntaxKind::INSERT_KW)
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct MergeUpdate {
+    pub(crate) syntax: SyntaxNode,
+}
+impl MergeUpdate {
+    #[inline]
+    pub fn set_token(&self) -> Option<SyntaxToken> {
+        support::token(&self.syntax, SyntaxKind::SET_KW)
+    }
+    #[inline]
+    pub fn update_token(&self) -> Option<SyntaxToken> {
+        support::token(&self.syntax, SyntaxKind::UPDATE_KW)
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct MergeWhenMatched {
+    pub(crate) syntax: SyntaxNode,
+}
+impl MergeWhenMatched {
+    #[inline]
+    pub fn condition(&self) -> Option<Expr> {
+        support::child(&self.syntax)
+    }
+    #[inline]
+    pub fn merge_action(&self) -> Option<MergeAction> {
+        support::child(&self.syntax)
+    }
+    #[inline]
+    pub fn and_token(&self) -> Option<SyntaxToken> {
+        support::token(&self.syntax, SyntaxKind::AND_KW)
+    }
+    #[inline]
+    pub fn matched_token(&self) -> Option<SyntaxToken> {
+        support::token(&self.syntax, SyntaxKind::MATCHED_KW)
+    }
+    #[inline]
+    pub fn then_token(&self) -> Option<SyntaxToken> {
+        support::token(&self.syntax, SyntaxKind::THEN_KW)
+    }
+    #[inline]
+    pub fn when_token(&self) -> Option<SyntaxToken> {
+        support::token(&self.syntax, SyntaxKind::WHEN_KW)
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct MergeWhenNotMatchedSource {
+    pub(crate) syntax: SyntaxNode,
+}
+impl MergeWhenNotMatchedSource {
+    #[inline]
+    pub fn condition(&self) -> Option<Expr> {
+        support::child(&self.syntax)
+    }
+    #[inline]
+    pub fn merge_action(&self) -> Option<MergeAction> {
+        support::child(&self.syntax)
+    }
+    #[inline]
+    pub fn and_token(&self) -> Option<SyntaxToken> {
+        support::token(&self.syntax, SyntaxKind::AND_KW)
+    }
+    #[inline]
+    pub fn by_token(&self) -> Option<SyntaxToken> {
+        support::token(&self.syntax, SyntaxKind::BY_KW)
+    }
+    #[inline]
+    pub fn matched_token(&self) -> Option<SyntaxToken> {
+        support::token(&self.syntax, SyntaxKind::MATCHED_KW)
+    }
+    #[inline]
+    pub fn not_token(&self) -> Option<SyntaxToken> {
+        support::token(&self.syntax, SyntaxKind::NOT_KW)
+    }
+    #[inline]
+    pub fn source_token(&self) -> Option<SyntaxToken> {
+        support::token(&self.syntax, SyntaxKind::SOURCE_KW)
+    }
+    #[inline]
+    pub fn then_token(&self) -> Option<SyntaxToken> {
+        support::token(&self.syntax, SyntaxKind::THEN_KW)
+    }
+    #[inline]
+    pub fn when_token(&self) -> Option<SyntaxToken> {
+        support::token(&self.syntax, SyntaxKind::WHEN_KW)
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct MergeWhenNotMatchedTarget {
+    pub(crate) syntax: SyntaxNode,
+}
+impl MergeWhenNotMatchedTarget {
+    #[inline]
+    pub fn condition(&self) -> Option<Expr> {
+        support::child(&self.syntax)
+    }
+    #[inline]
+    pub fn merge_action(&self) -> Option<MergeAction> {
+        support::child(&self.syntax)
+    }
+    #[inline]
+    pub fn and_token(&self) -> Option<SyntaxToken> {
+        support::token(&self.syntax, SyntaxKind::AND_KW)
+    }
+    #[inline]
+    pub fn by_token(&self) -> Option<SyntaxToken> {
+        support::token(&self.syntax, SyntaxKind::BY_KW)
+    }
+    #[inline]
+    pub fn matched_token(&self) -> Option<SyntaxToken> {
+        support::token(&self.syntax, SyntaxKind::MATCHED_KW)
+    }
+    #[inline]
+    pub fn not_token(&self) -> Option<SyntaxToken> {
+        support::token(&self.syntax, SyntaxKind::NOT_KW)
+    }
+    #[inline]
+    pub fn target_token(&self) -> Option<SyntaxToken> {
+        support::token(&self.syntax, SyntaxKind::TARGET_KW)
+    }
+    #[inline]
+    pub fn then_token(&self) -> Option<SyntaxToken> {
+        support::token(&self.syntax, SyntaxKind::THEN_KW)
+    }
+    #[inline]
+    pub fn when_token(&self) -> Option<SyntaxToken> {
+        support::token(&self.syntax, SyntaxKind::WHEN_KW)
+    }
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
@@ -10341,6 +10538,21 @@ pub enum MatchType {
     MatchSimple(MatchSimple),
 }
 
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub enum MergeAction {
+    MergeDelete(MergeDelete),
+    MergeDoNothing(MergeDoNothing),
+    MergeInsert(MergeInsert),
+    MergeUpdate(MergeUpdate),
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub enum MergeWhenClause {
+    MergeWhenMatched(MergeWhenMatched),
+    MergeWhenNotMatchedSource(MergeWhenNotMatchedSource),
+    MergeWhenNotMatchedTarget(MergeWhenNotMatchedTarget),
+}
+
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum OnCommitAction {
     DeleteRows(DeleteRows),
@@ -16082,6 +16294,132 @@ impl AstNode for Merge {
         &self.syntax
     }
 }
+impl AstNode for MergeDelete {
+    #[inline]
+    fn can_cast(kind: SyntaxKind) -> bool {
+        kind == SyntaxKind::MERGE_DELETE
+    }
+    #[inline]
+    fn cast(syntax: SyntaxNode) -> Option<Self> {
+        if Self::can_cast(syntax.kind()) {
+            Some(Self { syntax })
+        } else {
+            None
+        }
+    }
+    #[inline]
+    fn syntax(&self) -> &SyntaxNode {
+        &self.syntax
+    }
+}
+impl AstNode for MergeDoNothing {
+    #[inline]
+    fn can_cast(kind: SyntaxKind) -> bool {
+        kind == SyntaxKind::MERGE_DO_NOTHING
+    }
+    #[inline]
+    fn cast(syntax: SyntaxNode) -> Option<Self> {
+        if Self::can_cast(syntax.kind()) {
+            Some(Self { syntax })
+        } else {
+            None
+        }
+    }
+    #[inline]
+    fn syntax(&self) -> &SyntaxNode {
+        &self.syntax
+    }
+}
+impl AstNode for MergeInsert {
+    #[inline]
+    fn can_cast(kind: SyntaxKind) -> bool {
+        kind == SyntaxKind::MERGE_INSERT
+    }
+    #[inline]
+    fn cast(syntax: SyntaxNode) -> Option<Self> {
+        if Self::can_cast(syntax.kind()) {
+            Some(Self { syntax })
+        } else {
+            None
+        }
+    }
+    #[inline]
+    fn syntax(&self) -> &SyntaxNode {
+        &self.syntax
+    }
+}
+impl AstNode for MergeUpdate {
+    #[inline]
+    fn can_cast(kind: SyntaxKind) -> bool {
+        kind == SyntaxKind::MERGE_UPDATE
+    }
+    #[inline]
+    fn cast(syntax: SyntaxNode) -> Option<Self> {
+        if Self::can_cast(syntax.kind()) {
+            Some(Self { syntax })
+        } else {
+            None
+        }
+    }
+    #[inline]
+    fn syntax(&self) -> &SyntaxNode {
+        &self.syntax
+    }
+}
+impl AstNode for MergeWhenMatched {
+    #[inline]
+    fn can_cast(kind: SyntaxKind) -> bool {
+        kind == SyntaxKind::MERGE_WHEN_MATCHED
+    }
+    #[inline]
+    fn cast(syntax: SyntaxNode) -> Option<Self> {
+        if Self::can_cast(syntax.kind()) {
+            Some(Self { syntax })
+        } else {
+            None
+        }
+    }
+    #[inline]
+    fn syntax(&self) -> &SyntaxNode {
+        &self.syntax
+    }
+}
+impl AstNode for MergeWhenNotMatchedSource {
+    #[inline]
+    fn can_cast(kind: SyntaxKind) -> bool {
+        kind == SyntaxKind::MERGE_WHEN_NOT_MATCHED_SOURCE
+    }
+    #[inline]
+    fn cast(syntax: SyntaxNode) -> Option<Self> {
+        if Self::can_cast(syntax.kind()) {
+            Some(Self { syntax })
+        } else {
+            None
+        }
+    }
+    #[inline]
+    fn syntax(&self) -> &SyntaxNode {
+        &self.syntax
+    }
+}
+impl AstNode for MergeWhenNotMatchedTarget {
+    #[inline]
+    fn can_cast(kind: SyntaxKind) -> bool {
+        kind == SyntaxKind::MERGE_WHEN_NOT_MATCHED_TARGET
+    }
+    #[inline]
+    fn cast(syntax: SyntaxNode) -> Option<Self> {
+        if Self::can_cast(syntax.kind()) {
+            Some(Self { syntax })
+        } else {
+            None
+        }
+    }
+    #[inline]
+    fn syntax(&self) -> &SyntaxNode {
+        &self.syntax
+    }
+}
 impl AstNode for Move {
     #[inline]
     fn can_cast(kind: SyntaxKind) -> bool {
@@ -21037,6 +21375,119 @@ impl From<MatchSimple> for MatchType {
         MatchType::MatchSimple(node)
     }
 }
+impl AstNode for MergeAction {
+    #[inline]
+    fn can_cast(kind: SyntaxKind) -> bool {
+        matches!(
+            kind,
+            SyntaxKind::MERGE_DELETE
+                | SyntaxKind::MERGE_DO_NOTHING
+                | SyntaxKind::MERGE_INSERT
+                | SyntaxKind::MERGE_UPDATE
+        )
+    }
+    #[inline]
+    fn cast(syntax: SyntaxNode) -> Option<Self> {
+        let res = match syntax.kind() {
+            SyntaxKind::MERGE_DELETE => MergeAction::MergeDelete(MergeDelete { syntax }),
+            SyntaxKind::MERGE_DO_NOTHING => MergeAction::MergeDoNothing(MergeDoNothing { syntax }),
+            SyntaxKind::MERGE_INSERT => MergeAction::MergeInsert(MergeInsert { syntax }),
+            SyntaxKind::MERGE_UPDATE => MergeAction::MergeUpdate(MergeUpdate { syntax }),
+            _ => {
+                return None;
+            }
+        };
+        Some(res)
+    }
+    #[inline]
+    fn syntax(&self) -> &SyntaxNode {
+        match self {
+            MergeAction::MergeDelete(it) => &it.syntax,
+            MergeAction::MergeDoNothing(it) => &it.syntax,
+            MergeAction::MergeInsert(it) => &it.syntax,
+            MergeAction::MergeUpdate(it) => &it.syntax,
+        }
+    }
+}
+impl From<MergeDelete> for MergeAction {
+    #[inline]
+    fn from(node: MergeDelete) -> MergeAction {
+        MergeAction::MergeDelete(node)
+    }
+}
+impl From<MergeDoNothing> for MergeAction {
+    #[inline]
+    fn from(node: MergeDoNothing) -> MergeAction {
+        MergeAction::MergeDoNothing(node)
+    }
+}
+impl From<MergeInsert> for MergeAction {
+    #[inline]
+    fn from(node: MergeInsert) -> MergeAction {
+        MergeAction::MergeInsert(node)
+    }
+}
+impl From<MergeUpdate> for MergeAction {
+    #[inline]
+    fn from(node: MergeUpdate) -> MergeAction {
+        MergeAction::MergeUpdate(node)
+    }
+}
+impl AstNode for MergeWhenClause {
+    #[inline]
+    fn can_cast(kind: SyntaxKind) -> bool {
+        matches!(
+            kind,
+            SyntaxKind::MERGE_WHEN_MATCHED
+                | SyntaxKind::MERGE_WHEN_NOT_MATCHED_SOURCE
+                | SyntaxKind::MERGE_WHEN_NOT_MATCHED_TARGET
+        )
+    }
+    #[inline]
+    fn cast(syntax: SyntaxNode) -> Option<Self> {
+        let res = match syntax.kind() {
+            SyntaxKind::MERGE_WHEN_MATCHED => {
+                MergeWhenClause::MergeWhenMatched(MergeWhenMatched { syntax })
+            }
+            SyntaxKind::MERGE_WHEN_NOT_MATCHED_SOURCE => {
+                MergeWhenClause::MergeWhenNotMatchedSource(MergeWhenNotMatchedSource { syntax })
+            }
+            SyntaxKind::MERGE_WHEN_NOT_MATCHED_TARGET => {
+                MergeWhenClause::MergeWhenNotMatchedTarget(MergeWhenNotMatchedTarget { syntax })
+            }
+            _ => {
+                return None;
+            }
+        };
+        Some(res)
+    }
+    #[inline]
+    fn syntax(&self) -> &SyntaxNode {
+        match self {
+            MergeWhenClause::MergeWhenMatched(it) => &it.syntax,
+            MergeWhenClause::MergeWhenNotMatchedSource(it) => &it.syntax,
+            MergeWhenClause::MergeWhenNotMatchedTarget(it) => &it.syntax,
+        }
+    }
+}
+impl From<MergeWhenMatched> for MergeWhenClause {
+    #[inline]
+    fn from(node: MergeWhenMatched) -> MergeWhenClause {
+        MergeWhenClause::MergeWhenMatched(node)
+    }
+}
+impl From<MergeWhenNotMatchedSource> for MergeWhenClause {
+    #[inline]
+    fn from(node: MergeWhenNotMatchedSource) -> MergeWhenClause {
+        MergeWhenClause::MergeWhenNotMatchedSource(node)
+    }
+}
+impl From<MergeWhenNotMatchedTarget> for MergeWhenClause {
+    #[inline]
+    fn from(node: MergeWhenNotMatchedTarget) -> MergeWhenClause {
+        MergeWhenClause::MergeWhenNotMatchedTarget(node)
+    }
+}
 impl AstNode for OnCommitAction {
     #[inline]
     fn can_cast(kind: SyntaxKind) -> bool {
diff --git a/crates/squawk_syntax/src/postgresql.ungram b/crates/squawk_syntax/src/postgresql.ungram
index 6acd881c..92fe2683 100644
--- a/crates/squawk_syntax/src/postgresql.ungram
+++ b/crates/squawk_syntax/src/postgresql.ungram
@@ -928,8 +928,45 @@ Delete =
 Notify =
   'notify'
 
+MergeWhenMatched =
+  'when' 'matched' 
+  ('and' condition:Expr) 'then' MergeAction
+
+MergeWhenNotMatchedSource =
+  'when' 'not' 'matched' 'by' 'source' 
+  ('and' condition:Expr) 'then' MergeAction
+
+MergeWhenNotMatchedTarget =
+  'when' 'not' 'matched' ('by' 'target')? 
+  ('and' condition:Expr) 'then' MergeAction
+
+MergeWhenClause =
+  MergeWhenMatched
+| MergeWhenNotMatchedSource
+| MergeWhenNotMatchedTarget
+
+MergeDelete =
+ 'delete'
+
+MergeUpdate =
+  'update' 'set'
+
+MergeInsert =
+  'insert'
+
+MergeDoNothing =
+  'do' 'nothing'
+
+MergeAction =
+  MergeDelete
+| MergeUpdate
+| MergeInsert
+| MergeDoNothing
+
 Merge =
-  'merge'
+  'merge' 'into' 'only'? NameRef '*'? Alias? 
+  UsingClause
+  MergeWhenClause*
 
 Declare =
   'declare'