Returns the standard deviation of a set of numbers.
Parameters
Parameter |
Description |
|---|---|
expression |
Any numeric data type (FLOAT, REAL, or DOUBLE precision) expression. |
Returns
DOUBLE
Remarks
The formula used to calculate STDDEV is:
STDDEV returns a result of data type DOUBLE precision floating-point. If applied to the empty set, the result is NULL, which returns NULL for a one-element input set.
STDDEV does not support the keyword DISTINCT. A syntax error is returned if you use DISTINCT with STDDEV.
Standards and Compatibility
SQL—Vendor extension to ISO/ANSI SQL grammar.
Sybase—Not supported by Adaptive Server Enterprise.
Example
SELECT Salary FROM Employees WHERE DepartmentID = 300
|
Salary |
|---|
|
51432.000 |
|
57090.000 |
|
42300.000 |
|
43700.00 |
|
36500.000 |
|
138948.000 |
|
31200.000 |
|
58930.00 |
|
75400.00 |
The following statement returns the value 32617.8446712838471:
SELECT STDDEV ( Salary ) FROM Employees WHERE DepartmentID = 300
SELECT UnitPrice FROM Products WHERE Name = 'Tee Shirt'
|
Name |
UnitPrice |
|---|---|
|
Tee Shirt |
9.00 |
|
Tee Shirt |
14.00 |
|
Tee Shirt |
14.00 |
The following statement returns the value 2.88675134594813049:
SELECT STDDEV ( UnitPrice ) FROM Products WHERE Name = 'Tee Shirt'