Microsoft® SQL Server 2012 Unleashed

Identifying Search Arguments

A SARG is defined as a WHERE clause that compares a column to a constant. The format of a SARG is as follows:

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Column operator constant_expression [and...]

SARGs provide a way for the Query Optimizer to limit the rows searched to satisfy a query. The general goal is to match a SARG with an index to avoid a table scan. Valid operators for a SARG are =, >, <, >=, and <=, BETWEEN, and LIKE. Multiple SARGs can be combined with the AND clause. (A single index might match some or all of the SARGs ANDed together.) Following are examples of SARGs:

flag = 7

salary > 100000

city = 'Saratoga' and ...