sql - 如何在选择中使用变量

Question

如何在 select 中使用变量，如下所示：

 SELECT @V_BALANCE_PRIN=E.REC_PRINCIPAL_OS AS BALANCE_PRINCIPAL 
 FROM CR_TERMINATION_DTL E

Answer 1

You do need 2 queries to do this I believe, you can declare and assign the variable at the same time, but not select it. If you do a select @variable = (query) you don't get the result displayed, you just assign the value.

So I think the best you can do (to use the fewest lines) is:

DECLARE @V_BALANCE_PRIN NVARCHAR(10) = (SELECT E.REC_PRINCIPAL_OS FROM CR_TERMINATION_DTL E)
SELECT @V_BALANCE_PRIN AS BALANCE_PRINCIPAL

Obviously your data type will have to match, and you will also have to make sure that the subquery only returns a single value as pointed out by Justin, otherwise it will error.

Answer 2

两个查询怎么样：

SELECT @V_BALANCE_PRIN=E.REC_PRINCIPAL_OS FROM CR_TERMINATION_DTL E
SELECT @V_BALANCE_PRIN AS BALANCE_PRINCIPAL