| Syntax | Action |
|---|---|
| COUNT(value_expression) | Counts the total number of rows in the group for which value_expression is not null. |
| COUNT (DISTINCT value_expression) | Counts the total number of rows in the group for which value_expression is unique and not null. |
| COUNT(*) | Counts the total number of rows in the group of rows on which COUNT operates. |
COUNT is valid for any data type.