STDDEV_SAMP

Aggregate function.

The STDDEV_SAMP() function returns the sample standard deviation(the square root of VAR_SAMP()) of an expression.

警告

NULL values are not counted.

Syntax

STDDEV_SAMP(<expr>)

Arguments

Arguments	Description
<expr>	Any numerical expression

Return Type

double

Example

Create a Table and Insert Sample Data

CREATE TABLE height_data (
  id INT,
  person_id INT,
  height FLOAT
);

INSERT INTO height_data (id, person_id, height)
VALUES (1, 1, 5.8),
       (2, 2, 6.1),
       (3, 3, 5.9),
       (4, 4, 5.7),
       (5, 5, 6.3);

Query Demo: Calculate Sample Standard Deviation of Heights

SELECT STDDEV_SAMP(height) AS height_stddev_samp
FROM height_data;

Result

| height_stddev_samp |
|--------------------|
|      0.240         |