SQL結合WITH子句和Cursor

Question

如何在一個查詢中使用聲明的參數 ， WITH子句和游標

declare @TOP10 table (Cat Nvarchar(max),SubGUID uniqueidentifier)
declare @Sub uniqueidentifier
declare GUID_Cursor cursor FOR
(select SubGUID from dbo.Sub with(nolock) where year=2016)
;
with [MyTable] as
(
Select SubGUID, color from dbo.Cars with(nolock) where color ='blue'
)


open GUID_Cursor
fetch next from GUID_Cursor into @Sub
while @@FETCH_STATUS=0
begin
insert into @TOP10 (Cat,SubGUID)

select color,SubGUID from [MyTable]
where SubGUID=@Sub

fetch next from GUID_Cursor into @Sub

end
close GUID_Cursor
deallocate GUID_Cursor

select * from @TOP10

我只是找不到使用WITH子句后打開游標的方法。

誰能幫我？

Answer 1

好吧，除了代碼的邏輯（對我而言-根本不需要游標），您應該將CTE聲明移到更靠近使用它的地方。

;with [MyTable] as
(
    Select SubGUID, color from dbo.Cars with(nolock) where color ='blue'
)
insert into @TOP10 (Cat,SubGUID)    
select color,SubGUID from [MyTable]
where SubGUID=@Sub

但實際上，您的所有代碼都可以替換為：

declare @TOP10 table (Cat Nvarchar(max),SubGUID uniqueidentifier)

insert into @TOP10 (Cat,SubGUID)
select color,SubGUID 
from dbo.Cars with(nolock) 
where 
    color ='blue'
    and SubGUID in (select SubGUID from dbo.Sub with(nolock) where year=2016)

select * from @TOP10

Answer 2

我同意@AndyKorneyev，但出於實驗目的：

declare @crTest CURSOR,
        @name VARCHAR(1000),
        @type VARCHAR(1000)

set @crTest = CURSOR FAST_FORWARD FOR
    WITH cteObjs AS (
        SELECT TOP 10 NAME, type
        FROM sys.objects o
        )
    select name, type
    from cteObjs


OPEN @crTest

FETCH NEXT FROM @crTest
INTO @name, @type

WHILE @@FETCH_STATUS = 0
BEGIN
    PRINT @name
    PRINT @type

    FETCH NEXT FROM @crTest
    INTO @name, @type
END

CLOSE @crTest
DEALLOCATE @crTest

Answer 3

不想重復上述片段，但請注意， WITH子句結果集必須直接在其結尾處進行處理。

與@tableVar不同，cte返回的結果集的范圍在完整批處理中無效，因此必須緊隨其后的是SELECT，INSERT，UPDATE或DELETE語句 。 （有關詳細信息和示例，請參閱： https : //msdn.microsoft.com/zh-cn/library/ms175972.aspx或遵循其他答案之一）。

例如

    --> declare var: 
    declare @tableVar table (colOne int, colTwo nvarchar(30)
    );

    --> use cte: 
    with preOne as(select carId, color from pcUser with (nolock)
    )
    --> directly followed by insert:
    insert into @tableVar(userId, logInName)
      select colOne, colTwo from @tableVar;

    --> use var in cursor or anywhere else in the batch

雖然我不確定您的目標是什么，但也許短暫的加入可以達到目的：

select a.[SubGUID]
from [dbo].[Sub] as a with (nolock) 
    inner join [dbo].[Cars] as b with (nolock) on a.[SubGUID] = b.[SubGUID]
where a.[year] = 2016 and b.[color] = 'blue';

Answer 4

最后，我使用了諸如＃TOP10之類的臨時標簽。 我在查詢后刪除了它。 一旦我擺脫了with [MyTable] as我的參數就不再有問題了。

謝謝大家