3360
MariaDBERRORNotableDDL / IndexesHIGH confidence
Functional index not applicable
Production Risk
Low — DDL fails; no data is altered.
How to reproduce
trigger — this will error
trigger — this will error
-- Creating a functional index on an incompatible expression.
expected output
ERROR 3360 (HY000): Functional index on a column is not applicable.
Fix
Use compatible expression
Use compatible expression
CREATE INDEX idx ON t ((CAST(col AS CHAR)));
Why this works
Ensure the functional expression is supported for the target column type.
What not to do
✕
Sources
Official documentation ↗
MySQL 8.0 — 3360 ER_FUNCTIONAL_INDEX_NOT_APPLICABLE
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