computition與空的MS Access

Question

我的表名在MS接取 場AE ID，交易，金額CAPCON，

我的查詢是

Select distinct(CapCon.ID), 
(Select sum(amount) from CapCon as c 
    where c.id=CapCon.id 
    and transaction='Deposite') - 
(Select sum(amount) from CapCon as c 
    where c.id=CapCon.id and transaction='Withdrawal') 
as [Capital Contribution] from CapCOn 

中頻沒有取款的交易，沒有在[出資]輸出相應的ID

Answer 1

您需要在WHERE子句中檢查null：

Select distinct(CapCon.ID), 
    (Select sum(amount) from CapCon as c 
    where c.id=CapCon.id 
    and transaction='Deposite') - 
    (Select sum(amount) from CapCon as c 
    where c.id=CapCon.id 
    and transaction='Withdrawal' 
    and transaction is not null) 
as [Capital Contribution] from CapCOn