从两个不同的表中减去值
问题描述:
考虑表X:
A
-
1
2
3
3
6
考虑表Y:
A
-
0
4
2
1
9
如何编写查询以利用这两个表之间的差异来计算下表(例如表Z):
How do you write a query that takes the difference between these two tables, to compute the following table (say table Z):
A
-
1
-2
1
2
-3
答
不清楚您想要什么。
SELECT (SELECT SUM(A) FROM X) -
(SELECT SUM(A) FROM Y)
AS MyValue