STDDEV_POP

Aggregate function.

The STDDEV_POP() function returns the population standard deviation(the square root of VAR_POP()) of an expression.

tip

STD() or STDDEV() can also be used, which are equivalent but not standard SQL.

caution

NULL values are not counted.

Syntax

STDDEV_POP(<expr>)
STDDEV(<expr>)
STD(<expr>)

Arguments

Arguments	Description
<expr>	Any numerical expression

Return Type

double

Example

Create a Table and Insert Sample Data

CREATE TABLE test_scores (
  id INT,
  student_id INT,
  score FLOAT
);

INSERT INTO test_scores (id, student_id, score)
VALUES (1, 1, 80),
       (2, 2, 85),
       (3, 3, 90),
       (4, 4, 95),
       (5, 5, 100);

Query Demo: Calculate Population Standard Deviation of Test Scores

SELECT STDDEV_POP(score) AS test_score_stddev_pop
FROM test_scores;

Result

| test_score_stddev_pop |
|-----------------------|
|        7.07107        |