结合两个表中的两个SUM运算

Question

我有两个SQL操作（分别正常工作）：

SELECT SUM(Salary) AS StutorSum
FROM Stutor;

SELECT SUM(Salary) AS StudentAssistentSum
FROM StudentAssistent;

`

但问题是我无法将它们结合起来。 最终我想要三列：

1. StutorSum的专栏
2. 包含StudentAssistentSum的列
3. 包含两者总数的列

然而，我无法做到这一点，我尝试了很多东西，在互联网上搜索，但没有任何效果。

有人可以帮助我吗？

此致 净莲

Answer 1

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Answer 2

我建议将查询放在FROM子句中并进行算术运算：

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;