Count Function in SQLServer

Count Function in SQLServer

• Returns the number of items in a group.

Remarks :-

• COUNT(*) returns the number of items in a group. This includes NULL values and duplicates.
• COUNT(ALL expression) evaluates expression for each row in a group and returns the number of nonnull values.
• COUNT(DISTINCT expression) evaluates expression for each row in a group and returns the number of unique, nonnull values.