子查询列的总和

Question

I need to get the Sum of SubQuery Column. Here is what I am using, but it is giving error,

SELECT SUM (SELECT Col1 From Table1) FROM Table 2

Answer 1

Since you are not selecting anything from Table2, you can just do:

select sum(Col1) 
from Table1

Otherwise, you can do it like this:

select (
        select sum(Col1)
        from Table1
        ) as SumTable1Col1,
    Table2.SomeOtherCol
from Table2