SQL 多次使用一个 CTE

Use one CTE many times

提问by gigi

I have this, and i get an error at set total. Why can't i access a cte many times?

我有这个，但在设置总数时出现错误。为什么我不能多次访问 cte？

ALTER PROCEDURE [dbo].[GetLeaguePlayers]
(
    @idleague int,
    @pageNumber int,
    @pageSize int,
    @total int OUTPUT
)
AS
WITH CTEPlayers AS
(
    SELECT ROW_NUMBER() OVER (ORDER BY p.Name) AS RowNumber, p.Id, p.Name, t.Name AS Team
    FROM Players p INNER JOIN Teams t ON p.IdTeam=t.Id INNER JOIN Leagues l ON l.Id=t.IdLeague
    WHERE l.Id=@idleague
)
SELECT Id, Name
FROM CTEPlayers c
WHERE RowNumber>@pageSize*(@pageNumber-1) AND RowNumber<@pageSize*@pageNumber;
SET @total = ( SELECT COUNT(*) FROM CTEPlayers )

回答by JNK

A CTEis basically a disposable view. It only persists for a single statement, and then automatically disappears.

ACTE基本上是一次性视图。它只持续一个语句，然后自动消失。

Your options include:

您的选择包括：

• Redefine the CTEa second time. This is as simple as copy-paste from WITH...through the end of the definition to before your SET.

• Put your results into a #temptable or a @tablevariable

• Materialize the results into a real table and reference that

• Alter slightly to just SELECT COUNTfrom your CTE:

• CTE第二次重新定义。这就像从WITH...定义的末尾复制粘贴到您的SET.

• 将您的结果放入#temp表格或@table变量中

• 将结果具体化为一个真实的表格并参考

• 稍微更改为仅从SELECT COUNT您的 CTE：

.

.

SELECT @total = COUNT(*)
FROM Players p 
INNER JOIN Teams t 
    ON p.IdTeam=t.Id 
INNER JOIN Leagues l 
    ON l.Id=t.IdLeague
WHERE l.Id=@idleague

回答by om471987

None of the above answers are correct... You can execute CTE once and achieve the result you want.. here is the query

以上答案都不正确...您可以执行一次 CTE 并获得您想要的结果...这里是查询

ALTER PROCEDURE [dbo].[GetLeaguePlayers]
(
    @idleague int,
    @pageNumber int,
    @pageSize int,
    @total int OUTPUT
)
AS
WITH CTEPlayers AS
(
    SELECT p.Id, p.Name, t.Name AS Team
    FROM Players p INNER JOIN Teams t ON p.IdTeam=t.Id INNER JOIN Leagues l ON l.Id=t.IdLeague
    WHERE l.Id=@idleague
),
TotalCount AS
(
 SELECT COUNT(*) AS Total FROM CTEPlayers
),
Final_Result AS
(
 SELECT ROW_NUMBER() OVER (ORDER BY p.Name) AS RowNumber, p.Id, p.Name, t.Name AS Team,
  (SELECT Total FROM TotalCount) AS Total
    FROM CTEPlayers
)
SELECT Id, Name, @total = Total
FROM Final_Results c
WHERE RowNumber>@pageSize*(@pageNumber-1) AND RowNumber<@pageSize*@pageNumber;

回答by Lucero

A CTE is, per definition, only valid for one statement.

根据定义，CTE 仅对一个语句有效。

You can create an inline table-valued functionand then use this as often as you like. The inline function does what the name suggest; its query gets to be part of the query using it (in contrast to non-inline functions which are executed separately and used as a rowset).

您可以创建一个内联表值函数，然后随意使用它。内联函数顾名思义；它的查询成为使用它的查询的一部分（与单独执行并用作行集的非内联函数相反）。

回答by Arun Prasad E S

Using CTE Multiple Times to collect Data

多次使用 CTE 收集数据

;with CTEReminder AS
(
    Select r.ReminderID,r.IsVerificationRequired from ReminderTbl r      -- main table
),
FileTaskCountTempTbl   as     
    (
        select  COUNT(t.ReminderID) as FileTaskCount                     -- getting first result
            from TaskTbl t
                left join CTEReminder r on t.ReminderID = r.ReminderID          
    ),
FollowUpCountTempTbl  as
    (
        select COUNT(f.FollowUpID)  as Total                             -- getting second result
            from FollowUpTbl f              --cte not used here
    ),
MachineryRegularTaskCountTempTbl as
    (
        select  COUNT(t.ReminderID) as TotalCount                        -- getting third result
                from TaskTbl t
                    left join CTEReminder r on t.ReminderID = r.ReminderID                  
    ),
FinalResultTempTbl as
    (
        select COUNT(t.ReminderID)  as MachineryTaskCount,               -- getting fourth result
                (select * from MachineryRegularTaskCountTempTbl ) as MachineryRegularTaskCount,  -- Combining earlier results to last query 
                (select * from FollowUpCountTempTbl ) as FollowUpCount,   -- Combining earlier results to last query 
                (select * from FileTaskCountTempTbl ) as FileTaskCount   -- Combining earlier results to last query 
            from TaskTbl t
                left join CTEReminder r on t.ReminderID = r.ReminderID          
    )

select * from FinalResultTempTbl 

回答by Mushfiq Shaikh

Store the output in temporary table along-with the total count; set the output variable value and return the required columns from temporary table

将输出与总计数一起存储在临时表中；设置输出变量值并从临时表中返回所需的列

ALTER PROCEDURE [dbo].[GetLeaguePlayers]
(
    @idleague int,
    @pageNumber int,
    @pageSize int,
    @total int OUTPUT
)
AS
WITH CTEPlayers AS
(
    SELECT ROW_NUMBER() OVER (ORDER BY p.Name) AS RowNumber, p.Id, p.Name, t.Name AS Team
    FROM Players p INNER JOIN Teams t ON p.IdTeam=t.Id INNER JOIN Leagues l ON l.Id=t.IdLeague
    WHERE l.Id=@idleague
),
TotalCounter(TotalRecords) as
(select count(1) from CTEPlayers)


SELECT Id, Name, TotalRecords(select TotalRecords from TotalCounter) into #tmp
FROM CTEPlayers c
WHERE RowNumber>@pageSize*(@pageNumber-1) AND RowNumber<@pageSize*@pageNumber;

SET @total = ( SELECT TotalRecords FROM #tmp)

select Id, Name from $tmp

drop table #tmp

回答by Hugo Valer

In this case, I use this:

在这种情况下，我使用这个：

ALTER PROCEDURE [dbo].[GetLeaguePlayers]
(
 @idleague int,
 @pageNumber int,
 @pageSize int,
 @total int OUTPUT
)
AS

WITH CTEPlayers AS
(
    SELECT ROW_NUMBER() OVER (ORDER BY p.Name) AS RowNumber,    
        COUNT(1) OVER () AS RecordCount,
    p.Id, p.Name,   
    t.Name AS Team
    FROM Players p 
        INNER JOIN Teams t ON p.IdTeam=t.Id 
        INNER JOIN Leagues l ON l.Id=t.IdLeague
    WHERE l.Id=@idleague
)

SELECT RowNumber,
    CAST(CEILING(CAST(RecordCount AS FLOAT) / CAST(@pageSize AS FLOAT)) AS INT) PageCount,
    RecordCount,
    Id, 
    Name
FROM CTEPlayers c
WHERE RowNumber > @pageSize*(@pageNumber-1) AND RowNumber < @pageSize*@pageNumber;