Difference between revisions of "COUNT()"

Revision as of 16:26, 27 November 2009

Purpose

Returns the number of rows in a SELECT statement query

Syntax

COUNT(* | [DISTINCT] <expr>)

See Also

AGGREGATES, AVG(), SQL MAX(), MIN(), SELECT, SUM()

Description

Returns the number of rows in the query. If you specify DISTINCT, then only the rows which are unique in <expr> are counted. Specifying <expr> on its own returns the number of rows from the query for which <expr> is not NULL. If you specify the asterisk (*), then all rows are counted.

Example

// Get a count of all rows in the accounts table.
SELECT COUNT(*) Total FROM accounts;
 
// Get a count of jobs
SELECT COUNT(jobs) Jobs FROM employee;
 
// Get a count of distinct rows for jobs
SELECT COUNT(DISTINCT jobs) Jobs FROM employee;

Products

Recital Server, Recital