It is used to retrieve zero or more rows from one or more base tables, temporary tables, or views in a database. In most applications, SELECT
is the most commonly used Data Manipulation Language (DML) command. In specifying a SELECT
query, the user specifies a description of the desired result set, but they do not specify what physical operations must be executed to produce that result set. Translating the query into an optimal "query plan" is left to the database system, more specifically to the query optimiser.