Combining two SUM operations from two tables

Question

I have two operations for SQL (which are working properly, seperately):

SELECT SUM(Salary) AS StutorSum
FROM Stutor;

SELECT SUM(Salary) AS StudentAssistentSum
FROM StudentAssistent;

`

But the problem is that I cannot combine them. Eventually I want three columns as a result:

Column with the StutorSum
Column with the StudentAssistentSum
Column with the total of both

However I cannot make this happen, I tried a lot of things, searched on the internet, but nothing worked.

Could anyone help me?

Regards, Joren

What database are you using? Sql Server? MySql? Access? Oracle? Postgresql? And what is the key column for these tables (StudentID, Name, etc)? — Joel Coehoorn, Nov 01 '16 at 22:56

score 0 · Answer 1 · answered Nov 01 '16 at 22:58

0

SELECT 
    SUM(Salary) AS StutorSum,
    (SELECT SUM(Salary) FROM StudentAssistent) AS StudentAssistentSum,
    (SELECT SUM(Salary) FROM Stutor) + (SELECT SUM(Salary) FROM StudentAssistent) As Total
FROM Stutor;

answered Nov 01 '16 at 22:58

Joel Coehoorn

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score 0 · Answer 2 · answered Nov 01 '16 at 23:07

I would recommend putting the queries in the FROM clause and doing the arithmetic:

SELECT t.StutorSum, a.StudentAssistentSum,
       (t.StutorSum + a.StudentAssistentSum)
FROM (SELECT SUM(Salary) AS StutorSum
      FROM Stutor
     ) t CROSS JOIN
     (SELECT SUM(Salary) AS StudentAssistentSum
      FROM StudentAssistent
     ) a;

Combining two SUM operations from two tables

2 Answers2