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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