STDDEV_POP with Other Functions
STDDEV_POP can be combined with ordered analytical functions in a SELECT list, QUALIFY clause, or ORDER BY clause. See Window Aggregate Functions.
STDDEV_POP cannot be combined with aggregate functions within the same SELECT list, QUALIFY clause, or ORDER BY clause.
GROUP BY Affects STDDEV_POP Report Breaks
STDDEV_POP operates differently depending on whether there is a GROUP BY clause in the SELECT statement.
| GROUP BY Clause | Result |
|---|---|
| Specified | STDDEV_POP is reported for each individual group. |
| Omitted | STDDEV_POP is reported for all the rows in the sample. |
Measuring Standard Deviation of Population with STDDEV_POP
If your data represents only a sample of the entire population for the variable, then use the STDDEV_SAMP function. For information, see STDDEV_SAMP.
As the sample size increases, the values for STDDEV_SAMP and STDDEV_POP approach the same number, but use the more conservative STDDEV_SAMP calculation unless you are sure your data constitutes the entire population for the variable.