COVAR_POP Function in Oracle SQL

The COVAR_POP Function in Oracle SQL / PLSQL is used to calculate the population covariance of a set of numbers in pair.
Syntax for the using the COVAR_POP Function in Oracle SQL / PLSQL is:

SELECT COVAR_POP(expression_1, expression_2)
FROM table_name;

expression_1 and expression_2 are numeric expressions
The COVAR_POP function in Oracle SQL / PLSQL will eliminate all the pairs where expression_1 and expression_2 are having NULL values.

Examples:

Using COVAR_POP Function in Oracle SQL / PLSQL SELECT statement:

Suppose we have a table named ‘employee’ as shown below:

Employee_ID	Employee_Name	Salary	Department	Commission
101	Emp A	10000	Sales
102	Emp B	20000	IT	20
103	Emp C	28000	IT	20
104	Emp D	30000	Support
105	Emp E	32000	Sales	10
106	Emp F	40000	Sales	10
107	Emp G	12000	Sales	10
108	Emp H	12000	Support

If we write our COVAR_POP Function query as:

SELECT COVAR_POP(salary, commission)
FROM employee;

We will get ‘-6000’ as output