这是我要确定通过从
[Amount Accepted]
中减去[Amount Donated]
来获得的每个库中剩余血液的数据库图我试图选择抽取到银行中的血液和从银行中抽取的血液,但是我的问题是我不能减去两列
[blood drawn]
和[blood withdrawn]
,因为它们不在表格中相关
答案 0 :(得分:2)
您可以尝试以下操作。
foo()
答案 1 :(得分:0)
将派生表或公用表表达式中的所有选择都包装起来,然后将它们联接起来,例如
with donated as
( select ...
)
, accepted as
( select ...
)
select ...
from donated as a
join accepted as a
on a.[blood bank name] = d..[blood bank name]
答案 2 :(得分:0)
请注意,[Amount Accepted]
之前的'-'是键。
SELECT x.[Blood Bank Name], SUM(x.[Net Amount])
FROM
(
SELECT [Blood Bank Name], [Amount Donated] AS [Net Amount]
FROM [Donation Record]
UNION ALL
SELECT [Blood Bank Name], -[Amount Accepted] AS [Net Amount]
FROM [Transfusion Record]
) x
GROUP BY x.[Blood Bank Name]