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The non-standard function STDDEV is provided for compatibility with other databases. It is semantically identical to STDDEV_SAMP.
STDDEV_SAMP evaluates the statistical sample standard deviation for each member of the group.
STDDEV_SAMP(expression) = SQRT(VAR_SAMP(expression))
Syntax
STDDEV_SAMP(expression)
Semantics
expression |
(INTEGER, BIGINT, DOUBLE PRECISION, or INTERVAL) contains at least one |
Examples
SELECT STDDEV_SAMP(b) FROM aggtest;
stddev_samp
------------------
57282.1641693241
(1 row)
column reference