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SQL

DATEDIFF in WHERE Clause Disables Indexes

- 17.12.25 - ErcanOPAK

This looks innocent:

WHERE DATEDIFF(day, CreatedAt, GETDATE()) = 0

❌ Why it’s bad

  • Forces full scan

  • Index becomes useless

βœ… Fix

WHERE CreatedAt >= CAST(GETDATE() AS date)

 

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