variance/var_pop¶
This function is used to return the variance of a column.
Syntax¶
variance(col),
var_pop(col)
Parameters¶
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:
warehouseId _c1 city1 19.23124 city2 17.23344 city3 12.43425