SingleStore DB

COUNT

Aggregate function. Counts the number of rows passed in. If the value of a given item is NULL, the row is not counted.

Syntax
COUNT ( [DISTINCT] expression )
Arguments
  • DISTINCT: optional keyword. If present, will count the number of unique values.

  • expression: any expression. This may be a column name, the result of another function, or a math operation. The special operator "*" is also allowed, to indicate pure row counting.

Return Type

An integer.

Examples
SELECT COUNT(*) FROM people;
+----------+
| COUNT(*) |
+----------+
|     5000 |
+----------+

SELECT COUNT(middle_name) AS middles FROM people;
+----------+
|  middles |
+----------+
|     1238 |
+----------+

SELECT COUNT(DISTINCT middle_name) AS middles FROM people;
+----------+
|  middles |
+----------+
|      213 |
+----------+