In relational databases, a condition (or predicate) in a query is said to be sargable if the DBMS engine can take advantage of an index to speed up the execution of the query. The term is derived from a contraction of Search ARGument ABLE.
A query failing to be sargable is known as non-sargable query and typically has a negative effect on query time, so one of the steps in query optimization is to convert them to be sargable. The effect is similar to searching for a specific term in a book that has no index, beginning at page one each time, instead of jumping to a list of specific pages identified in an index.
The typical situation that will make a SQL query non-sargable is to include in the WHERE clause a function operating on a column value. The WHERE clause is not the only clause where sargability can matter; it can also have an effect on ORDER BY, GROUP BY and HAVING clauses. The SELECT clause, on the other hand, can contain non-sargable expressions without adversely affecting the performance.
=, >, <, >=, <=, BETWEEN, LIKE, IS [NOT] NULL<>, IN, OR, NOT IN, NOT LIKE