sql查詢返回null

Question

我使用完全相同的查詢從兩個表中獲取數據。當我不使用c.IsReceived = 0部件時，它將返回日期，但在使用時不會返回任何內容。在RepDailyCollection中有的IsReceived = 0。你認爲我做錯了什麼？這是在2005年的SQL Server。 thnak你！

Select 
    distinct RepDailyInfo.Date 
from 
    RepDailyInfo 
left outer join 
    RepDailyCollection c 
on 
    c.RepDailyCollectionID = RepDailyInfo.RepDailyInfoID 
where 
    RepDailyInfo.RepID = 205 and c.IsReceived = 0 

編輯：

當我使用類似的其他存儲過程正常工作。

Select i.Date 
--i.RepDailyInfoID, i.RepID, i.TypeofDayID, i.CommuniTeeID, sum(cast(c.AmountSold as numeric(10,2))) as AmountSold, 
-- sum(cast (c.AmountCollected as numeric(10,2))) as AmountCollected, c.NewCompanyName,c.PaymentMethod, 
-- c.TypeofCreditCard, c.CheckNumber, c.Invoice, c.Spots, TypeofDay.TypeofDay, CommuniTee.City, CommuniTee.State, 
-- CommuniTee.year, SalesRep_Info.FirstName, SalesRep_Info.LastName 
from RepDailyInfo i 
left outer join RepDailyCollection c on i.RepDailyInfoID = c.RepDailyInfoID 
left outer join TypeOfDay on TypeOfDay.TypeofDayID = i.TypeofDayID 
left outer join SalesRep_Info on SalesRep_Info.RepID = i.RepID 
left outer join CommuniTee on CommuniTee.CommuniTeeID = i.CommuniTeeID 
where i.RepID = 205 and c.IsReceived = 0 
group by i.RepDailyInfoID, i.Date, i.TypeofDayID, i.CommuniTeeID, SalesRep_Info.FirstName, TypeofDay.TypeofDay, 
CommuniTee.City, CommuniTee.State, CommuniTee.year, SalesRep_Info.FirstName, 
SalesRep_Info.LastName, i.RepID, c.NewCompanyName, c.PaymentMethod, c.TypeofCreditCard, c.CheckNumber, c.Invoice, c.Spots 
order by SalesRep_Info.FirstName desc 

Answer 1

這裏有很多錯誤。

在第一個查詢您有：

Select 
    distinct RepDailyInfo.Date 
from 
    RepDailyInfo 
left outer join 
    RepDailyCollection c 
on 
    c.RepDailyCollectionID = RepDailyInfo.RepDailyInfoID 
where 
    RepDailyInfo.RepID = 205 and c.IsReceived = 0 

即使你說的「左外連接」，由於where子句你不妨說內連接。

無論如何，這個查詢與第二個不匹配。在第二個查詢中，您正在將RepDailyCollection加入RepDailyInfo的RepDailyInfoID。在第一個查詢中，您將加入完全不同的列。

Answer 2

如果你有 「LEFT JOIN ... ON ... = RepDailyInfo.RepDailyInfoID」，應該說實際上是 「LEFT JOIN ... ON ... = RepDailyInfo.RepDailyCollectionID」？

Answer 3

難道它是一個varchar/char字段？

c.IsReceived = '0' 

Answer 4

有可能在RepDailyCollection記錄與IsReceived = 0和RepID = 205，但如果沒有在RepDailyInfo任何記錄與205 REPID則沒有記錄會因爲你的where子句中返回。

根據您的陳述與RepDailyCollection

有行IsReceived = 0 REPID = 205

這聽起來像你的where子句應該是：

c.RepID = 205 and c.IsReceived = 0 

代替的

RepDailyInfo.RepID = 205 and c.IsReceived = 0 

Answer 5

爲您的測試..你可以做下面的查詢..

Select distinct c.IsReceived from RepDailyInfo 
left outer join RepDailyCollection c on c.RepDailyCollectionID = RepDailyInfo.RepDailyInfoID 
where RepDailyInfo.RepID = 205 and c.IsReceived = 0 

如果你能看到0，則此欄必須是VARCHAR2數據類型..

然後用下面的查詢\

Select distinct RepDailyInfo.Date from RepDailyInfo 
left outer join RepDailyCollection c on c.RepDailyCollectionID = RepDailyInfo.RepDailyInfoID 
where RepDailyInfo.RepID = 205 and c.IsReceived = '0'