corr¶
This function is used to return the correlation coefficient between two columns of numerical values.
Syntax¶
corr(col1, col2)
Parameters¶
Parameter | Mandatory | Type | Description |
|---|---|---|---|
col1 | Yes | DOUBLE, BIGINT, INT, SMALLINT, TINYINT, FLOAT, or DECIMAL | Columns with a data type of numeric. If the value is of any other type, NULL is returned. |
col2 | Yes | DOUBLE, BIGINT, INT, SMALLINT, TINYINT, FLOAT, or DECIMAL | Columns with a data type of numeric. If the values are of any other type, NULL is returned. |
Return Values¶
The return value is of the DOUBLE type.
Example Code¶
Calculates the correlation coefficient between the inventory (items) and the price of all products. An example command is as follows:
select corr(items,price) from warehouse;
The command output is as follows:
_c0 1.242355
When used with group by, it groups all offerings by warehouse (warehourseId) and returns the correlation coefficient between the inventory (items) and the price of offerings within each group. An example command is as follows:
select warehourseId, corr(items,price) from warehourse group by warehourseId;
The command output is as follows:
warehouseId _c1 city1 0.43124 city2 0.53344 city3 0.73425