Add IBM Db2 dialect support by ShubhamKapoor992 · Pull Request #7275 · tobymao/sqlglot

ShubhamKapoor992 · 2026-03-12T06:39:25Z

Summary

This PR adds support for IBM Db2 dialect to SQLGlot, enabling parsing and transpilation of Db2 SQL syntax.

Changes

✅ Added sqlglot/dialects/db2.py with full Db2 dialect implementation
✅ Added comprehensive test suite in tests/dialects/test_db2.py
✅ Updated sqlglot/dialects/__init__.py to register Db2 dialect
✅ Updated README.md to list Db2 as officially supported dialect

Features Implemented

Data Types

Db2-specific types: CLOB, DBCLOB, DECFLOAT, GRAPHIC, VARGRAPHIC
Type mappings: BOOLEAN → SMALLINT, TEXT → CLOB, etc.

SQL Syntax

FETCH FIRST n ROWS ONLY syntax
OFFSET n ROWS syntax
CURRENT DATE and CURRENT TIMESTAMP (without underscores)
String concatenation with || operator

Functions

POSSTR (string position)
VARCHAR_FORMAT (date/time formatting)
DAYOFWEEK, DAYOFYEAR extracts
DAYS function for date arithmetic
MIDNIGHT_SECONDS function

Transformations

Boolean values → 0/1 conversion
Date arithmetic with +/- operators
CAST to CHAR special handling
MAX/MIN → GREATEST/LEAST conversion

Testing

✅ All 194 test cases pass
✅ Covers basic SQL operations (SELECT, INSERT, UPDATE, DELETE)
✅ Tests Db2-specific syntax and functions
✅ Tests data type conversions
✅ Tests joins, aggregations, CTEs, and complex queries

Compatibility

Follows SQLGlot dialect patterns
No breaking changes to existing functionality
All existing tests continue to pass

Documentation

Added Db2 to the supported dialects table in README.md
Marked as "Community" support level
Inline code comments for Db2-specific behavior

…ons.py conflict

tobymao · 2026-03-12T06:46:31Z

 | BigQuery | Official |
 | ClickHouse | Official |
 | Databricks | Official |
+| Db2 | Official |


i'm not sure if we will end up merging this PR, i'll let the core team decide, but it certainly will not be official. please change this to community

georgesittas · 2026-03-12T12:01:20Z

Thank you for the PR @ShubhamKapoor992.

The core team does not have review bandwidth for new community contributed dialects at the moment, so I'll go ahead and close this PR for now. Will let you know if this changes in the future to re-open.

ShubhamKapoor992 · 2026-03-12T12:16:50Z

Hi @georgesittas

Thank you for the update.

This contribution is driven by the IBM customer requirement and we want to support it officially, and we are also working on enabling Db2 support in Ibis, sqlmesh which internally relies on SQLGlot. Having the Db2 dialect available in SQLGlot would therefore help unblock the release and integration on the Ibis and sqlmesh side as well.

We completely understand the bandwidth constraints of the core team. If there is any way we can assist in reducing the review effort (for example, by addressing specific feedback or aligning the implementation with project guidelines), we would be happy to help.

Please let us know if there is any possibility of reconsidering the PR or if there is an alternative path we should follow for moving this forward.

Thank you again for your time and guidance.

ShubhamKapoor992 · 2026-03-12T12:58:11Z

@georgesittas

Adding to what i stated earlier I am from IBM organization and we want to support it officially, so please don't consider it as community contribution. For official contribution if you required any changes from our end, do let us know.

georgesittas · 2026-03-12T14:45:27Z

@ShubhamKapoor992 thank you for expressing your interest to help.

Despite your team taking on the burden of implementing the dialect, the SQLGlot core team still has to spend review cycles on every PR, because once it is merged we will be the ones responsible for maintaining the code and ensuring its quality adheres to our standards and existing conventions.

In order for us to consider getting this in, your team first needs to demonstrate that it can make high quality contributions to SQLGlot. Thus, the suggestion is to find issues and/or improvements that can be made to the codebase and solve them. If the incoming PRs are of high quality over the course of, let's say, two weeks, then we can get this dialect in, as long as you're committed to maintaining it.

Otherwise, there's also the option of developing the dialect as a plugin. From the README:

Plugin Dialects (supported since v28.6.0) are third-party dialects developed and maintained in external repositories by independent contributors. These dialects are not part of the SQLGlot codebase and are distributed as separate packages. The SQLGlot team does not provide support or maintenance for plugin dialects — please direct any issues or feature requests to their respective repositories. See Creating a Dialect Plugin below for information on how to build your own.

Lastly, regarding:

[...] we want to support it officially, so please don't consider it as community contribution.

Please note that both official and community -developed dialects are shipped with SQLGlot. The difference is who drives their development, which, in the latter case, is the community. For example, Exasol is shipped with SQLGlot but the core team is not involved in its development (that is, other than reviewing the incoming PRs.)

## Summary Add a custom [SQLGlot](https://github.com/tobymao/sqlglot) dialect for DataFusion and a `to_datafusion_sql` function that transpiles SQL from any supported source dialect to DataFusion SQL. This is the first step in decoupling the `TableTransformer` API from DataFusion internals. Instead of returning a DataFusion DataFrame (leaking the execution engine to users), the `TableTransformer` will return a SQL string and its dialect. The data loader will then use SQLGlot to translate that SQL to DataFusion for execution. It will be used in #496. We maintain the DataFusion dialect in-repo rather than contributing it upstream to SQLGlot because the SQLGlot maintainers don't have capacity to review more community dialects right now ([source](tobymao/sqlglot#7275 (comment))). Context: #496 (comment) ## Changes - [ ] Client-facing API Changes - [ ] Internal API Changes - [ ] Bug Fixes - [x] New Features - [ ] Performance Improvements - [ ] Code Style - [ ] Refactoring - [ ] Documentation - [x] Tests **DataFusion dialect** (`datafusion_sql.py`): custom SQLGlot dialect with DataFusion-specific function mappings (e.g. `SIZE` → `cardinality`, `ARRAY()` → `make_array`, `CURRENT_TIMESTAMP()` → `now()`), type mappings (e.g. `CHAR`/`TEXT` → `VARCHAR`, `BINARY` → `BYTEA`), and identifier/normalization rules. **SQL translator** (`datafusion_sql.py`): `to_datafusion_sql(sql, source_dialect)` accepts any supported source dialect (spark, postgres, mysql, etc.) and transpiles to DataFusion. When source_dialect is `"datafusion"` it returns the SQL unchanged. Validates the dialect with a clear error listing all supported options. **Dependency**: added `sqlglot>=29.0.0`. ## Testing Done - [ ] Manually Tested on local docker setup. Please include commands ran, and their output. - [x] Added new tests for the changes made. - [ ] Updated existing tests to reflect the changes made. - [ ] No tests added or updated. Please explain why. If unsure, please feel free to ask for help. - [ ] Some other form of testing like staging or soak time in production. Please explain. Parametrized transpilation tests cover spark, mysql, postgres, and datafusion identity. Edge case tests for unsupported dialects and multi-statement errors. E2E test executes transpiled SQL against DataFusion and validates output data. ``` make check # All checks passed (ruff, mypy) make test # 19 dialect tests pass ``` # Additional Information - [ ] Breaking Changes - [ ] Deprecations - [x] Large PR broken into smaller PRs, and PR plan linked in the description. This is the first PR. Follow-up PRs will integrate the translator into the `TableTransformer` API and data loader pipeline. --------- Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

ShubhamKapoor992 · 2026-03-30T06:35:00Z

Hi @georgesittas,

As per your suggestion, we’ve contributed and successfully merged three high-quality PRs to build community trust:

#7294
#7361
#7395

We’d really appreciate it if you could reconsider our PR for review when you have bandwidth. Looking forward to your feedback!

Shubham Kapoor added 4 commits February 2, 2026 12:41

Db2 dialect added

fcef757

changes in README.md for Db2 support

4b91d55

Merge main branch into feature/db2-sqlglot-dialect - resolve expressi…

70c4e0c

…ons.py conflict

Readme.md change

e9c4ecf

tobymao reviewed Mar 12, 2026

View reviewed changes

Shubham Kapoor added 4 commits March 12, 2026 12:18

change from Official to Community

903f637

Fix linting and formatting issues in DB2 dialect

4180500

Fix mypyc compatibility: Move Db2 parser to separate file

e0fb962

changes in dialect for db2 parser

ceed9db

georgesittas closed this Mar 12, 2026

georgesittas mentioned this pull request Mar 12, 2026

WIP: Add initial Vertica dialect support for SELECT (requesting early feedback) #7277

Closed

robreeves mentioned this pull request Mar 13, 2026

[DataLoader] Add DataFusion SQLGlot dialect for SQL transpilation linkedin/openhouse#501

Merged

17 tasks

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Add IBM Db2 dialect support#7275

Add IBM Db2 dialect support#7275
ShubhamKapoor992 wants to merge 8 commits intotobymao:mainfrom
ShubhamKapoor992:feature/db2-sqlglot-dialect

ShubhamKapoor992 commented Mar 12, 2026 •

edited

Loading

Uh oh!

tobymao Mar 12, 2026

Uh oh!

ShubhamKapoor992 Mar 12, 2026

Uh oh!

georgesittas commented Mar 12, 2026

Uh oh!

ShubhamKapoor992 commented Mar 12, 2026 •

edited

Loading

Uh oh!

ShubhamKapoor992 commented Mar 12, 2026

Uh oh!

georgesittas commented Mar 12, 2026 •

edited

Loading

Uh oh!

ShubhamKapoor992 commented Mar 30, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

Conversation

ShubhamKapoor992 commented Mar 12, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Summary

Changes

Features Implemented

Data Types

SQL Syntax

Functions

Transformations

Testing

Compatibility

Documentation

Uh oh!

tobymao Mar 12, 2026

Choose a reason for hiding this comment

Uh oh!

ShubhamKapoor992 Mar 12, 2026

Choose a reason for hiding this comment

Uh oh!

georgesittas commented Mar 12, 2026

Uh oh!

ShubhamKapoor992 commented Mar 12, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

ShubhamKapoor992 commented Mar 12, 2026

Uh oh!

georgesittas commented Mar 12, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

ShubhamKapoor992 commented Mar 30, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

ShubhamKapoor992 commented Mar 12, 2026 •

edited

Loading

ShubhamKapoor992 commented Mar 12, 2026 •

edited

Loading

georgesittas commented Mar 12, 2026 •

edited

Loading