2

我只想知道如何在 SQl Server中编写CTE包含？If Exists我曾尝试在下面写一个 CTE，我正在使用If Exists语句来选择天气记录是否存在。如果记录不存在，那么我正在分配默认值但我收到错误

'关键字'if'附近的语法不正确

。请帮助我修复此错误并指导我编写此 CTE。请在我写的 CTE 下面找到：-

Alter procedure St_Proc_GetTeamProductionReport      
@mindate DateTime,                        
@maxdate DateTIme,    
@userID varchar(50)                    
as                                          
Begin                                          
     set NoCount on; 
with    
ProductionCTE(CalendarDate,RoleID,UserID,UserECode,UserName,ImmediateSupervisor,NatureOfWorkName,RegionProjectName,CountyName,WorkTypeName,TaskName,VolumneProcessed,TimeSpent,Comment)    
as    
(    
    if exists
    (
        select P.CalendarDate,U.RoleID,U.UserID,U.UserECode,U.UserName,U.ImmediateSupervisor,N.NatureofWorkName,    
        R.RegionProjectName,C.Countyname,W.WorktypeName,T.TaskName,P.VolumeProcessed,P.Timespent,P.Comment    
        from production P inner join NatureOfWork N    
        on N.NatureofWorkID=P.natureofworkid    
        inner join dbo.RegionAndProjectInfo R    
        on R.RegionProjectID=P.RegionProjectID    
        inner join county C    
        on C.countyid=P.countyid    
        inner join worktype W    
        on W.Worktypeid=P.worktypeID    
        inner join task T    
        on T.taskid=P.TaskID    
        inner join UserInfo U    
        on U.Userid=P.userid    
        where P.userid=@userID  and ( convert(varchar, P.CalendarDate, 101) )  between (
        convert(varchar, @mindate, 101) ) and ( convert(varchar, @maxdate, 101) )  
    )
    else
    (
        Select '2012-09-14 13:41:52' as CalendarDate,
        2 as RoleID,'938' as UserID,
        (select Userecode from Userinfo where userid=@userID) as UserECode,
        (select UserName from Userinfo where userid=@userID)as UserName,
        (select ImmediateSupervisor from Userinfo where userid=@userID)as ImmediateSupervisor,
        'BP' as NatureOfWorkName,
        'CO Processing' as RegionProjectName,
        'Adams' as CountyName,
        'Quality' as WorkTypeName,
        'Corrections ' as TaskName,
        5 as VolumneProcessed,
        '01:00' as TimeSpent,
        'test' as Comment
        ) 

    union all

    select P.CalendarDate,U.RoleID,U.UserID,U.UserECode,U.UserName,U.ImmediateSupervisor,N.NatureofWorkName,    
    R.RegionProjectName,C.Countyname,W.WorktypeName,T.TaskName,P.VolumeProcessed,P.Timespent,P.Comment    
    from production P inner join NatureOfWork N    
    on N.NatureofWorkID=P.natureofworkid    
    inner join dbo.RegionAndProjectInfo R    
    on R.RegionProjectID=P.RegionProjectID    
    inner join county C    
    on C.countyid=P.countyid    
    inner join worktype W    
    on W.Worktypeid=P.worktypeID    
    inner join task T    
    on T.taskid=P.TaskID    
    inner join UserInfo U    
    on U.Userid=P.userid    
    inner join ProductionCTE    
    on U.ImmediateSupervisor=ProductionCTE.UserECode    

    where P.IsTaskCompleted=1   and ( convert(varchar, P.CalendarDate, 101) )  between (
    convert(varchar, @mindate, 101) ) and ( convert(varchar, @maxdate, 101) )         
)  
select  distinct CONVERT(VARCHAR,CalendarDate,20) as CalendarDate,UserECode,UserName,NatureOfWorkName,RegionProjectName,CountyName,WorkTypeName,TaskName,VolumneProcessed,TimeSpent,Comment from ProductionCTE where  RoleID=1    
end

去

当我删除此 If Exist 语句时，CTE它工作正常，但在添加IF Exists语句后出现错误。

4

3 回答 3

2

你不能IF EXISTS以这种方式使用。一个公用表表达式只能包含一个 select 语句，这是不可能的if condition SELECT THIS else SELECT THAT。

看起来您正在尝试向查询返回的结果集中添加一个额外的创建行。您可以通过将 CTE 实现为将返回单个新行的表值函数来实现此目的。

http://msdn.microsoft.com/en-gb/library/ms191165(v=sql.105).aspx

于 2013-02-06T11:23:08.680 回答
1

如果您想构建一个如果第一个不返回任何行，则UNION只能从第二个获得结果，您可以使用. 因此，您可以将真正的查询放在第一个中，将所需的默认值放在第二个中，并获得您想要的结果。SELECTSELECTRANK()SELECT

我没有你的表格和数据，所以我不会尝试重写你的查询。但我会用这个来说明：

;With WithDefaults as (
    select name,0 as Rank from sys.objects
    union all
    select 'abc',1 --Default if no results
), Ranked as (
    select *,RANK() OVER (ORDER BY Rank) as Rnk from WithDefaults
)
select * from Ranked where Rnk = 1

返回（在我尝试过的大部分空数据库上）98 个结果，其中没有name abc. 如果我们强制第一个SELECT不返回结果：

    select name,0 as Rank from sys.objects where 1 = 2

我们现在使用name abc.

希望您能看到这如何应用于您的原始查询。

于 2013-02-06T13:51:04.723 回答
0

您不能在 CTE 中使用 IF EXISTS。但是你可以修改函数的逻辑

例子：

alter procedure St_Proc_GetTeamProductionReport
@mindate DateTime,                        
@maxdate DateTIme,    
@userID varchar(50)                    
as                                          
Begin                                          
set NoCount on;
;with    
ProductionCTE(CalendarDate,RoleID,UserID,UserECode,UserName,ImmediateSupervisor,NatureOfWorkName,RegionProjectName,CountyName,WorkTypeName,TaskName,VolumneProcessed,TimeSpent,Comment)    
as    
(               
        select P.CalendarDate,U.RoleID,U.UserID,U.UserECode,U.UserName,U.ImmediateSupervisor,N.NatureofWorkName,    
        R.RegionProjectName,C.Countyname,W.WorktypeName,T.TaskName,P.VolumeProcessed,P.Timespent,P.Comment, 1 AS cnt 
        from production P inner join NatureOfWork N    
        on N.NatureofWorkID=P.natureofworkid    
        inner join dbo.RegionAndProjectInfo R    
        on R.RegionProjectID=P.RegionProjectID    
        inner join county C    
        on C.countyid=P.countyid    
        inner join worktype W    
        on W.Worktypeid=P.worktypeID    
        inner join task T    
        on T.taskid=P.TaskID    
        inner join UserInfo U    
        on U.Userid=P.userid    
        where P.userid=@userID  and ( convert(varchar, P.CalendarDate, 101) )  between (
        convert(varchar, @mindate, 101) ) and ( convert(varchar, @maxdate, 101) )  
        UNION ALL
        Select '2012-09-14 13:41:52' as CalendarDate,
        2 as RoleID,'938' as UserID,
        (select Userecode from Userinfo where userid=@userID) as UserECode,
        (select UserName from Userinfo where userid=@userID)as UserName,
        (select ImmediateSupervisor from Userinfo where userid=@userID)as ImmediateSupervisor,
        'BP' as NatureOfWorkName,
        'CO Processing' as RegionProjectName,
        'Adams' as CountyName,
        'Quality' as WorkTypeName,
        'Corrections ' as TaskName,
        5 as VolumneProcessed,
        '01:00' as TimeSpent,
        'test' as Comment, 0 
     ), ProductionCTE2 AS    
    (    
    SELECT TOP(SELECT CASE WHEN COUNT(*) = 0 THEN 1 ELSE COUNT(*) END FROM ProductionCTE WHERE cnt = 1)
           CalendarDate,RoleID,UserID,UserECode,UserName,ImmediateSupervisor,NatureofWorkName,    
           RegionProjectName,Countyname,WorktypeName,TaskName,VolumeProcessed,Timespent,Comment
    FROM ProductionCTE2           
    union all
    select P.CalendarDate,U.RoleID,U.UserID,U.UserECode,U.UserName,U.ImmediateSupervisor,N.NatureofWorkName,    
    R.RegionProjectName,C.Countyname,W.WorktypeName,T.TaskName,P.VolumeProcessed,P.Timespent,P.Comment    
    from production P inner join NatureOfWork N    
    on N.NatureofWorkID=P.natureofworkid    
    inner join dbo.RegionAndProjectInfo R    
    on R.RegionProjectID=P.RegionProjectID    
    inner join county C    
    on C.countyid=P.countyid    
    inner join worktype W    
    on W.Worktypeid=P.worktypeID    
    inner join task T    
    on T.taskid=P.TaskID    
    inner join UserInfo U    
    on U.Userid=P.userid    
    inner join ProductionCTE    
    on U.ImmediateSupervisor=ProductionCTE.UserECode
    where P.IsTaskCompleted=1   and ( convert(varchar, P.CalendarDate, 101) )  between (
    convert(varchar, @mindate, 101) ) and ( convert(varchar, @maxdate, 101) )         
)  
select  distinct CONVERT(VARCHAR,CalendarDate,20) as CalendarDate,UserECode,UserName,NatureOfWorkName,RegionProjectName,CountyName,WorkTypeName,TaskName,VolumneProcessed,TimeSpent,Comment 
from ProductionCTE2
where  RoleID=1    
end
于 2013-02-06T13:34:01.627 回答