fix: Fix invalid MSSQL SQL when DISTINCT and FETCH are combined #5630
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When a query combines DISTINCT and FETCH (pagination) in MSSQL, the compiler was generating ORDER BY (SELECT NULL) which is invalid because MSSQL requires ORDER BY items to appear in the SELECT list when DISTINCT is used. This fix extracts the first column from the projection for use in ORDER BY when DISTINCT is present, producing valid MSSQL syntax. Fixes PRQL#5628 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <[email protected]>
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Dec 20, 2025
Expands test_mssql_distinct_fetch() to cover additional code paths: - ExprWithAlias: column with alias uses alias for ORDER BY - Multiple columns: first column is used for ORDER BY Follow-up to PRQL#5630 to improve code coverage. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <[email protected]>
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Great, thanks @max-sixty 🎉 |
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Summary
SELECT DISTINCTwithFETCH(pagination)ORDER BY (SELECT NULL)was used, but MSSQL requires ORDER BY items to appear in the SELECT list when DISTINCT is usedFixes #5628
Test plan
test_mssql_distinct_fetch()covering the reported issue🤖 Generated with Claude Code