VAR ( [ ALL | DISTINCT ] expression )
Applies the function to all values. ALL is the default.
Specifies that each unique value is considered.
Is an expression of the exact numeric or approximate numeric data type category, except for the bit data type. Aggregate functions and subqueries are not permitted.
If VAR is used on all items in a SELECT statement, each value in the result set is included in the calculation. VAR can be used with numeric columns only. Null values are ignored.
The following example returns the variance for all bonus values in the SalesPerson table.