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stddev,stddev_pop,std

Description​

Returns the population standard deviation of the expr expression. Since v2.5.10, this function can also be used as a window function.

Syntax​

STDDEV(expr)

Parameters​

expr: the expression. If it is a table column, it must evaluate to TINYINT, SMALLINT, INT, BIGINT, LARGEINT, FLOAT, DOUBLE, or DECIMAL.

Return value​

Returns a DOUBLE value. The formula is as follows, where n represents the row count of the table:

image

Examples​

mysql> SELECT stddev(lo_quantity), stddev_pop(lo_quantity) from lineorder;
+---------------------+-------------------------+
| stddev(lo_quantity) | stddev_pop(lo_quantity) |
+---------------------+-------------------------+
|   14.43100708360797 |       14.43100708360797 |
+---------------------+-------------------------+

See also​

stddev_samp

keyword​

STDDEV,STDDEV_POP,POP