Updated on 2023-11-03 GMT+08:00

variance/var_pop

This function is used to return the variance of a column.

Syntax

variance(col), 
var_pop(col)

Parameters

Table 1 Parameter

Parameter

Mandatory

Description

col

Yes

Columns with a data type of numeric.

If the value is of any other type, NULL is returned.

Return Values

The return value is of the DOUBLE type.

Example Code

  • Calculates the variance of all offering inventories (items). An example command is as follows:
    select variance(items) from warehouse; 
    -- It is equivalent to the following statement:
    select var_pop(items) from warehouse;

    The command output is as follows:

    _c0        
    203.42352 
  • When used with group by, it groups all offerings by warehouse (warehourseId) and returns the variance of the offering inventory (items) in the same group. An example command is as follows:
    select warehourseId, variance(items) from warehourse group by warehourseId; 
    -- It is equivalent to the following statement:
    select warehourseId, var_pop(items) from warehourse group by warehourseId;

    The command output is as follows:

    1
    2
    3
    4
    warehouseId _c1        
    city1    19.23124   
    city2    17.23344   
    city3    12.43425