Question

我的查询没有做我想要的，我不知道如何解决这个问题：

DECLARE @RoomMap TABLE
    (ID int IDENTITY(1,1),
    SourceRoom int,--> SourceRoomID
    SourceSiteID int,
    TargetRoom int, -->DemoRoomID
    TargetSiteID int
    )

INSERT INTO @RoomMap
(SourceRoom, SourceSiteID)
SELECT tblControls_Rooms.ID, @origSiteID
FROM tblControls_Rooms
WHERE SiteID = @OrigSiteID

INSERT INTO @RoomMap
(TargetRoom, TargetSiteID)
SELECT tblControls_Rooms.ID, @NewSiteID
FROM tblControls_Rooms
WHERE SiteID = @newSiteID

INSERT INTO DemoRoomMap 
(DemoRoomID, SourceRoomID)
SELECT TargetRoom, SourceRoom
FROM @RoomMap

当我运行时，这是DemoRoomMap表：

TargetRoom  SourceRoom
    332 2
    333 3
    334 4
    335 5
    336 6
    337 9
    338 10

运行上述查询时的结果：

TargetRoom  SourceRoom
NULL    1942
NULL    1943
NULL    1944
NULL    1945
NULL    1946
2025    NULL
2026    NULL
2027    NULL
2028    NULL

如您所见，有NULL个值我真的不想插入！我该怎样摆脱它们？

Answer 1

您可以通过在其中插入值来摆脱它们。请注意，此语句不会在TargetRoom中插入值：

INSERT INTO @RoomMap
(SourceRoom, SourceSiteID)
SELECT tblControls_Rooms.ID, @origSiteID
FROM tblControls_Rooms
WHERE SiteID = @OrigSiteID

此外，后续声明不会将值插入SourceRoom：

INSERT INTO @RoomMap
(TargetRoom, TargetSiteID)
SELECT tblControls_Rooms.ID, @NewSiteID
FROM tblControls_Rooms
WHERE SiteID = @newSiteID

因此，当您完成后，您将获得一组没有TargetRoom的行和一组没有SourceRoom的行。

Answer 2

DECLARE @RoomMap TABLE
(ID int IDENTITY(1,1),
SourceRoom int,--> SourceRoomID
SourceSiteID int,
TargetRoom int, -->DemoRoomID
TargetSiteID int
)

INSERT INTO @RoomMap
(SourceRoom, SourceSiteID, TargetRoom TargetSiteID )
SELECT S.ID, @origSiteID, T.ID, @NewSiteID
FROM 
(
    SELECT ID FROM tblControls_Rooms WHERE SiteID = @OrigSiteID
) S
CROSS JOIN
(
    SELECT ID FROM tblControls_Rooms WHERE SiteID = @NewSiteID
) T

带有Insert语句的SQL Server NULL值

2 个答案: