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:

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:

Image flag = 7

salary > 100000

city = 'Saratoga' and ...

Get Microsoft® SQL Server 2012 Unleashed now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.