STD,STDDEV,STDDEV_POP

Description

Returns the standard deviation of the expr expression

Alias

• STD
• STDDEV_POP

Syntax

STDDEV(<expr>)

Parameters

Parameter	Description
<expr>	The value to be calculated standard deviation, supports type Double.

Return Value

Return the sample standard deviation of the expr expression as Double type. If there is no valid data in the group, returns NULL.

Examples

-- Create sample tables
CREATE TABLE score_table (
    student_id INT,
    score DOUBLE
) DISTRIBUTED BY HASH(student_id)
PROPERTIES (
    "replication_num" = "1"
);

-- Insert test data
INSERT INTO score_table VALUES
(1, 85),
(2, 90),
(3, 82),
(4, 88),
(5, 95);

-- Calculate the standard deviation of all students' scores
SELECT STDDEV(score) as score_stddev
FROM score_table;

+-------------------+
| score_stddev      |
+-------------------+
| 4.427188724235729 |
+-------------------+