Replacing Null Values with Mean Value of the Column in Grid DB

Question

So, I was working with GridDB NodeJs Connector, I know the query to find out the null values which shows the records/rows:

SELECT * FROM employees where employee_salary = NaN;

But I want to replace the null values of the column with the mean value of the column, in order to maintain the data consistency for data analysis. How do I do that in GridDB?

The Employee table looks like the following:

 employee_id   employee_salary   first_name     department
 
---------------+---------------+--------------+--------------

  0                               John           Sales
  
  1                 60000         Lisa           Development
  
  2                 45000         Richard        Sales
  
  3                 50000         Lina           Marketing
  
  4                 55000         Anderson       Development