Categories:: Data metric functions

STDDEV (system data metric function)¶

Returns the standard deviation value for the specified column in a table.

The STDDEV system data metric function is optimized to calculate the standard deviation for a single column and provides greater performance when compared to calling the STDDEV function.

This topic provides the syntax for calling the function directly. To learn how to associate the function with a table or view so it runs at regular intervals, see Associate a DMF to automate data quality checks.

Syntax¶

SNOWFLAKE.CORE.STDDEV(<query>)

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Arguments¶

query: Specifies a SQL query that projects a single column.

Allowed data types¶

The column projected by the query must have one of the following data types:

FLOAT
NUMBER

Returns¶

The function returns a NUMBER value.

Example¶

Measure the standard deviation value for the salary column in a table:

SELECT SNOWFLAKE.CORE.STDDEV(
  SELECT
    salary
  FROM hr.tables.empl_info
);

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+------------------------------+
|       SNOWFLAKE.CORE.STDDEV( |
|                       SELECT |
|                       SALARY |
|     FROM HR.TABLES.EMPL_INFO |
|                            ) |
|------------------------------|
|               8407.615595399 |
+------------------------------+