Alphabet Soup 101: Sargable

Programming industry is notorious for alphabet soup of acronyms and jargons. If some concept or phrase don't have any acronym or catchy word yet, someone will make a made-up one.



When I'm talking to someone about database optimization, I'm referring to an index-friendly condition as index-friendly condition. Could it be any harder than that? But lo and behold, there's a handy word for that programming discipline, it's called SARGable

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 has an effect in query time, so one of the steps in query optimization is convert them to be sargable.

The typical thing that will make a sql query non-sargable is to include a function in left part of a condition of a Where clause.

Read the rest of the article at: http://en.wikipedia.org/wiki/Sargable

http://www.sql-server-performance.com/2007/t-sql-where/