筛选出查询中的 NULL

Question

以下子查询返回一些空值和一些值。 我想选择非空的行，我该怎么做？

        ,(select distinct LEDGERTABLE.ACCOUNTNAME
    FROM ledgertrans 
    Where Salesline.SalesID = #tempCMs.SALESID and salesline.DIMENSION = 
        (Select top 1 Ledgertrans.Dimension
        From LedgerTrans
            Where Ledgertrans.Voucher = #tempCms.InvoiceID and LedgerTrans.AccountNum = Ledgertable.Accountnum)
 ) As 'Account'

谢谢

Answer 1

用IS NOT NULL过滤 NULL

试试这个：

(select distinct LEDGERTABLE.ACCOUNTNAME
    FROM ledgertrans 
    Where Salesline.SalesID = #tempCMs.SALESID and salesline.DIMENSION = 
        (Select top 1 Ledgertrans.Dimension
        From LedgerTrans
            Where Ledgertrans.Voucher = #tempCms.InvoiceID 
            and LedgerTrans.AccountNum = Ledgertable.Accountnum
            AND LEDGERTABLE.ACCOUNTNAME IS NOT NULL)
 ) As 'Account'

NULL值不会用相等检验（!= NULL）过滤，因为NULL值是未知的，因此不能确定相等性。

Answer 2

将AND LEDGERTABLE.ACCOUNTNAME IS NOT NULL添加到WHERE子句中。