hardDSA

How do you optimize a slow SQL query?

Q: How do you optimize a slow SQL query?

Examine the **execution plan** (`EXPLAIN`) to find full scans, then: add appropriate indexes, avoid `SELECT *`, filter early, prefer joins over correlated subqueries, ensure statistics are current, avoid functions on indexed columns in WHERE, and paginate large results.

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Examine the execution plan (EXPLAIN) to find full scans, then: add appropriate indexes, avoid SELECT *, filter early, prefer joins over correlated subqueries, ensure statistics are current, avoid functions on indexed columns in WHERE, and paginate large results.

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