more mysql, sql, window-functions How come I cannot calculate the running sum on the column I am ordering ? For example, I have this Candidates table: Candidates table: +————-+————+——–+ employee_id experience salary +————-+————+——–+ 1 Junior 10000 9 Junior 10000 2 Senior 20000 11 Senior 20000 13 Senior 50000 4 Junior