count

Count the rows of an aggregate result set

Syntax

COUNT({* | [DISTINCT] column_var})

Arguments

*	All columns of the result set.
column_var	The name of a column or one of the tables referenced in the FROM clause.

Description

This function computes the total number of rows in each aggregate. If DISTINCT is specified with a column name reference then duplicate values of the name column are not included in the count.

A "select count(*) from table_name" quickly returns the number of rows contained in the specified table.

A "select count(*) from table_spec" returns the cardinality (the number of rows) of the specified table. RaimaDB automatically maintains this count for every table allowing the count to be returned from a single call that does not require a database access. SQL fetches the count value without having to apply a lock to the table. Hence, the value that is fetched is "dirty"—meaning that it will account for any uncommitted INSERT or DELETE statements that have been executed by other connections. In order to fetch a "clean" value, the application should either first execute a "start trans read only" or an explicit "lock table" statement prior to the "select count(*) from table_spec".

Example

open nsfawards;

select count(*) from award;

       count(*)
         132365

select state, count(*) from sponsor, award 
	where sponsor_nm = name
	group by 1 having count(*) > 100;
state              count(*)
AK                      637
AL                     1085
AR                      406
AZ                     2917
CA                    16923
CO                     3353
	...
VT                      333
WA                     3218
WI                     2582
WV                      294
WY                      382