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:
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
keyword
STDDEV,STDDEV_POP,POP