All Functions WHERE Clause HAVING Clause GROUP BY Clause FUNCTION: STDEV SELECT STD(field) AS [expression] FROM table [WHERE ...] [GROUPBY ...] [HAVING ...]   The STDEV function is one of the aggregate functions that are used to calculate statistical information for a specified numeric field in a query. The other aggregate functions are: AVG, COUNT, MAX, MIN, STDEVP, SUM, VAR, VARP. Note that all of these functions return a single value.   The STDEV function finds the standard deviation by using a portion, called a sample, of the total number of values in a field. This is a time saver when dealing with extremely large tables and can be shown to be statistically valid. In comparison, the STDEVP function uses all of the values to calculate the standard deviation. There must be at least two values in the field or the standard deviation will not be calculated and a NULL is returned.   This code finds the standard deviation of the age of the MediCare patients in a hospital (by using a sample) and stores that information in SDAge.   SELECT Var(Age) AS [SDAge] FROM MediCarePatients Copyright 1999-2001 by Infinite Software Solutions, Inc. All rights reserved. Trademark Information