Teradata Cumulative SUM using SUM WINDOW function

SUM window Cumulative Function:

SUM window function allows cumulative aggregate to be calculated. Teradata equivalent is CSUM function. To get cumulative SUM we use UNBOUNDED PRECEDING as follows: SELECT        EMPLOYEEID,DEPARTMENTNO,SALARY, SUM(SALARY) OVER (  ORDER        BY DEPARTMENTNO ROWS  UNBOUNDED PRECEDING  ) FROM        EMPLOYEE2; Employeeid DepartmentNo Salary Cumulative Sum(Salary) 5 100 5000 5000 9 100 9000 14000 1 100 1000 15000 6 200 6000 21000 124 200 12345.11 33345.11 10 200 10000 43345.11 2 200 2000 45345.11 11 300 11000 56345.11 7 300 7000 63345.11 3 300 3000 66345.11 12 400 12000 78345.11 4 400 4000 82345.11 8 400 8000 90345.11 144 400 12345.11 102690.2 Cumulative Sum is nothing but sequential aggregation . Note that the Column title indicates that its 'Cumulative SUM' We can reset the cumulative SUM by making use of PARTITION BY clause as follows: SELECT        EMPLOYEEID,DEPARTMENTNO,SALARY, SUM(SALARY) OVER (  PARTITION BY DEPARTMENTNO ORDER        BY DEPARTMENTNO ROWS  UNBOUNDED PRECEDING  ) FROM        EMPLOYEE2; Employeeid DepartmentNo Salary Cumulative Sum(Salary) 1 100 1000 1000 5 100 5000 6000 9 100 9000 15000 124 200 12345.11 12345.11 10 200 10000 22345.11 6 200 6000 28345.11 2 200 2000 30345.11 7 300 7000 7000 3 300 3000 10000 11 300 11000 21000 4 400 4000 4000 12 400 12000 16000 8 400 8000 24000 144 400 12345.11 36345.11