Question

我想在RepDailyInfo时RepDailyCollection.IsReceived = 0以及RepDailyCollection确实拥有特定RepDailyInfoID的记录时从Select distinct RepDailyInfo.Date from RepDailyInfo left outer join RepDailyCollection c on c.RepDailyInfoID = RepDailyInfo.RepDailyInfoID where c.IsReceived = 0 or c.IsReceived = null表中获取日期。这可能在sql server 2005中吗？

{{1}}

Answer 1

将条件移动到连接的ON子句中，因为否则您需要连接来查找WHERE子句中要引用的行的行：

Select distinct RepDailyInfo.Date 
from RepDailyInfo 
left outer join RepDailyCollection c 
    on c.RepDailyInfoID = RepDailyInfo.RepDailyInfoID
    and (c.IsReceived = 0 or c.IsReceived is null)

另请注意在or周围使用括号，因为“或”优先于“和”而没有括号，最终会得到“（A和B）或C”

Answer 2

您可能想要

where IsNull(c.IsReceived,0) = 0

Answer 3

是的，但您必须在连接中过滤右侧的连接：

Select distinct RepDailyInfo.Date 
from RepDailyInfo 
left outer join RepDailyCollection c 
    on c.RepDailyInfoID = RepDailyInfo.RepDailyInfoID
   and (c.IsReceived = 0 
    or c.IsReceived is null)

Answer 4

WHERE子句在OUTER JOIN之后进行过滤。如果您不想要这种行为，请将WHERE子句移到ON的{{1}}子句中，如下所示：

JOIN

使用左外连接时，即使记录不存在，也返回行

4 个答案: