3615
MySQLERRORNotableDDLHIGH confidence
Cannot drop column referenced by a functional index
Production Risk
Low — DDL fails; no data loss occurs.
How to reproduce
trigger — this will error
trigger — this will error
ALTER TABLE t DROP COLUMN a; -- where a functional index uses a
expected output
ERROR 3615 (HY000): Cannot drop column 'a' because it is referenced in a functional index.
Fix
Drop the functional index first
Drop the functional index first
ALTER TABLE t DROP INDEX func_idx; ALTER TABLE t DROP COLUMN a;
Why this works
Removes the functional index dependency before the column drop.
What not to do
✕
Version notes
Sources
Official documentation ↗
MySQL 8.0 — 3615 ER_CANNOT_DROP_COLUMN_REFERENCED_IN_FUNCTIONAL_INDEX
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