COUNT and COUNT DISTINCT functions

The COUNT function counts the rows defined by the expression. The COUNT DISTINCT function computes the number of distinct non-NULL values in a column or expression. It eliminates all duplicate values from the specified expression before doing the count.

Syntax

COUNT (column)

COUNT (DISTINCT column)

Arguments

column

The target column that the function operates on.

Data types

The COUNT function and the COUNT DISTINCT function supports all argument data types.

The COUNT DISTINCT function returns BIGINT.

Examples

Count all of the users from the state of Florida.

select count (identifier) from users where state='FL';

Count all of the unique venue IDs from the EVENT table.

select count (distinct (venueid)) as venues from event;