STDDEV_SAMP and VAR_SAMP
Learn about the changes introduced to ensure that the STDDEV_SAMP and VAR_SAMP built-in aggregate functions (UDAFs) are in compliance with the SQL:2011 standards.
Before upgrade to CDP
VAR_SAMP aggregate functions were not in
compliance with SQL:2011 standards and returns '0' when the function is applied to a set with a
single element. The functions are expected to return NULL.
After upgrade to CDP
HIVE-17375 fixes the issue and ensures that these functions comply with SQL:2011 standards. The functions now return NULL when they are applied to either an empty set or a set with a single element.