Return estimates of the variance for a population or a population sample represented as a set of values contained in a specified field on a query.
Var ( expr )
VarP ( expr )
The expr placeholder represents a string expression identifying the field that contains the numeric data you want to evaluate or an expression that performs a calculation using the data in that field. Operands in expr can include the name of a table field, a constant, or a function (which can be either intrinsic or user-defined but not one of the other SQL aggregate functions ).
The VarP function evaluates a population, and the Var function evaluates a population sample.
If the underlying query contains fewer than two records, the Var and VarP functions return a Null value, which indicates that a variance cannot be calculated.
You can use the Var and VarP functions in a query expression or in an SQL statement.