MSSQL: Support standalone BEGIN...END blocks #2186
Conversation
Signed-off-by: Guan-Ming (Wesley) Chiu <105915352+guan404ming@users.noreply.github.com>
Signed-off-by: Guan-Ming (Wesley) Chiu <105915352+guan404ming@users.noreply.github.com>
| if parser.parse_keyword(Keyword::BEGIN) { | ||
| if parser.peek_keyword(Keyword::TRANSACTION) | ||
| || parser.peek_keyword(Keyword::WORK) | ||
| || parser.peek_keyword(Keyword::TRY) | ||
| || parser.peek_keyword(Keyword::CATCH) | ||
| || parser.peek_keyword(Keyword::DEFERRED) | ||
| || parser.peek_keyword(Keyword::IMMEDIATE) | ||
| || parser.peek_keyword(Keyword::EXCLUSIVE) | ||
| || parser.peek_token_ref().token == Token::SemiColon | ||
| || parser.peek_token_ref().token == Token::EOF | ||
| { | ||
| parser.prev_token(); | ||
| return None; | ||
| } | ||
| Some(parser.parse_begin_exception_end()) |
There was a problem hiding this comment.
would a condition like this do what we want?
if parse.peek_keywords(BEGIN, TRANSACTION) {
None
} else if parse_keyword(BEGIN) {
Some(parser.parse_begin_exception_end())
}its not super clear to me why the current logic looks at WORK, TRY etc keywords?
There was a problem hiding this comment.
Thanks for the review. These keywords are checked because parse_begin() handles more than just BEGIN TRANSACTION. It also handles WORK, TRY, CATCH, DEFERRED, IMMEDIATE, EXCLUSIVE (since MsSql's supports_start_transaction_modifier() returns true), as well as bare BEGIN;. If any of these are missed, they'd be incorrectly routed to parse_begin_exception_end() and fail to parse.
For example, BEGIN TRY ... END TRY is valid MSSQL syntax. If we only check for BEGIN TRANSACTION, then BEGIN TRY would fall through to parse_begin_exception_end(), which would try to parse TRY as a SQL statement and fail. because TRY is supposed to be handled as a
datafusion-sqlparser-rs/src/parser/mod.rs
Lines 17938 to 17939 in c8b7f7c
There was a problem hiding this comment.
Feel free to let me know if there are any not clear, thanks!
2 participants
Why
I'm currently building sql-parser npm pkg for js/ts named sqlparser-ts, which powered by this amazing repo via WebAssembly! When reconstruct all dialects test in typescript, I find some issue and decide to contribute back to upstream~
The MSSQL dialect previously had no way to parse standalone BEGIN...END blocks.
BEGIN SELECT 1; ENDwould fail because parse_begin() only handles BEGIN TRANSACTION.How
wires MSSQL into the same path like BigQuery and Snowflake