Tsql add alter constraint if exists #6957
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PR Summary
Added support for DROP CONSTRAINT IF EXISTS syntax in T-SQL dialect, allowing conditional constraint dropping in ALTER TABLE statements.
- Added new parsing rule in
src/sqlfluff/dialects/dialect_tsql.pyto supportIF EXISTSclause in DROP CONSTRAINT statements - Added test case in
test/fixtures/dialects/tsql/alter_table.sqldemonstrating the new syntax - Extended ALTER TABLE grammar in
test/fixtures/dialects/tsql/alter_table.ymlwith parsing rules for the IF EXISTS clause - Implementation matches Microsoft Azure Databricks SQL reference documentation
3 files reviewed, no comments
Edit PR Review Bot Settings | Greptile
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keraion
approved these changes
Jun 20, 2025
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Brief summary of the change made
Allows for a DROP CONSTRAINT IF EXISTS sequence to te parsed correctly in tsql.
fixes #6956
Are there any other side effects of this change that we should be aware of?
Does not seem likely
Pull Request checklist
Please confirm you have completed any of the necessary steps below.
Included test cases to demonstrate any code changes, which may be one or more of the following:
.ymlrule test cases intest/fixtures/rules/std_rule_cases..sql/.ymlparser test cases intest/fixtures/dialects(note YML files can be auto generated withtox -e generate-fixture-yml).test/fixtures/linter/autofix.Added appropriate documentation for the change.
Created GitHub issues for any relevant followup/future enhancements if appropriate.