Avoid implicit type conversions in comparisons

Avoid implicit type conversions in comparisons | BeforeMerge Rules | BeforeMerge

Why this matters

When the two sides of a comparison differ in type, MySQL implicitly casts every row, which prevents index use and can produce surprising matches. Compare a column to a literal of its own type.

-- Bad: phone is VARCHAR; numeric literal forces a per-row cast
SELECT * FROM users WHERE phone = 5551234;
 
-- Good: matching string type uses the index
SELECT * FROM users WHERE phone = '5551234';

Why This Matters

Related Rules

Catch this automatically on every PR

Why this matters