3294
MySQLWARNINGCriticalQuery OptimizationHIGH confidence
Optimizer hint is not applicable to this query
Production Risk
Low — warning only; query executes without the hint.
How to reproduce
trigger — this will error
trigger — this will error
SELECT /*+ NO_INDEX_MERGE(t1) */ * FROM t2;
expected output
Warning 3294: Hint NO_INDEX_MERGE is not applicable for query.
Fix
Remove inapplicable hint
Remove inapplicable hint
SELECT * FROM t2;
Why this works
Remove hints that reference tables not present in the query.
What not to do
✕
Sources
Official documentation ↗
MySQL 8.0 — 3294 ER_NOT_HINT_APPLICABLE
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