Categories:: Data metric functions

VARIANCE (system data metric function)¶

Returns the variance value for the specified column in a table. Use this function to detect unexpected changes in data spread.

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

Syntax¶

SNOWFLAKE.CORE.VARIANCE(<query>)

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 FLOAT value.

Example¶

Measure the variance for the salary column in a table:

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