The index that the query ignores
A table has an index on created_at. This query is slow, and the plan shows
a full table scan:
sql
SELECT * FROM orders WHERE YEAR(created_at) = 2026;
The index exists and is healthy. Why is it not used?
A table has an index on created_at. This query is slow, and the plan shows
a full table scan:
sql
SELECT * FROM orders WHERE YEAR(created_at) = 2026;
The index exists and is healthy. Why is it not used?