What does 'sargable' mean?

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Accepted Answer

Sargable stands for 'Search ARGument ABLE' - a condition that the query optimizer can match against an index. Wrapping a column in a function usually breaks sargability: WHERE YEAR(created_at) = 2024 forces a full scan, but WHERE created_at >= '2024-01-01' AND created_at < '2025-01-01' can use an index on created_at. The same applies to leading wildcards in LIKE - WHERE name LIKE '%smith' cannot use a standard B-tree index, but WHERE name LIKE 'smith%' can.