SQL STDDEV : MySQL on population standard deviation

MySQL aggregate function STDDEV() returns population standard deviation of the input field. It returns NULL if no matching row is found.

STDDEV() is synonym of the sql function STDDEV_POP().
STD() is also synonym of the sql function STDDEV_POP().

Here are some examples using our student table.

SELECT STDDEV(mark) , STD(mark), STDDEV_POP(mark) FROM `student`

Output is here

STDDEV(mark)	STD(mark)	STDDEV_POP(mark)
16.49766163752223	16.49766163752223	16.49766163752223

By using FORMAT()

Restrict decimal places by using FORMAT()

SELECT FORMAT(STDDEV(mark),2) FROM `student`

Output is here

FORMAT(STDDEV(mark),2)
16.50

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Subhendu Mohapatra

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STDDEV: population standard deviation

By using FORMAT()

Subhendu Mohapatra