Computes the statistical variance of a sample consisting of a numeric-expression, as a double, and returns the variance of a set of numbers. var and variance are aliases of var_samp, and use the same syntax.
var_samp ( [ all | distinct] expression )
applies var_samp to all values. all is the default.
eliminates duplicate values before var_samp is applied.
is any numeric datatype (float, real, or double) expression.
Lists the average and variance of the advances for each type of book in the pubs2 database:
select type, avg(advance) as "avg", var_samp(advance) as "variance" from titles where total_sales > 2000 group by type order by type
var_samp returns a result of double-precision floating-point datatype. If applied to the empty set, the result is NULL.
Figure 2-4: The formula for sample-related statistical aggregate functions
ANSI SQL – Compliance level: Transact-SQL extension.
Any user can execute var_samp.
For general information about aggregate functions, see “Aggregate functions” in Adaptive Server Enterprise Reference Manual: Building Blocks.
Functions stddev_pop, stddev_samp, var_pop
