Question

我想将公用表表达式的结果集与现有表连接起来。使用以下查询中给出的group by子句会出现问题。有谁能告诉我如何加入这两张桌子？。

With CTEQuery
as
(SELECT     StudentOnlineExamCourseAnswer.StudentID, StudentOnlineExamCourseAnswer.OnlineExamID, StudentOnlineExamCourseAnswer.CourseID, 
                      StudentOnlineExamCourseAnswer.CentreID,
case QuestionBank.ComplexLevelID when 1 then (2) when 2 then (4) when 3 then (6) when 4 then (8) when 5 then (10) end as Mark
FROM         QuestionBank INNER JOIN
                      StudentOnlineExamCourseAnswer ON QuestionBank.Answer = StudentOnlineExamCourseAnswer.Answer AND 
                      QuestionBank.QuestionID = StudentOnlineExamCourseAnswer.QuestionID) 
select StudentID, OnlineExamID ,CourseID , CentreID , sum(Mark) as 'Total Marks' from CTEQuery 
group by StudentID, OnlineExamID ,CourseID , CentreID

Answer 1

您可以为单个选择定义多个CTE，每个CTE可以引用先前定义的CTE。所以你可以这样做：

With CTEQuery
as
(SELECT     StudentOnlineExamCourseAnswer.StudentID, StudentOnlineExamCourseAnswer.OnlineExamID, StudentOnlineExamCourseAnswer.CourseID, 
                      StudentOnlineExamCourseAnswer.CentreID,
case QuestionBank.ComplexLevelID when 1 then (2) when 2 then (4) when 3 then (6) when 4 then (8) when 5 then (10) end as Mark
FROM         QuestionBank INNER JOIN
                      StudentOnlineExamCourseAnswer ON QuestionBank.Answer = StudentOnlineExamCourseAnswer.Answer AND 
                      QuestionBank.QuestionID = StudentOnlineExamCourseAnswer.QuestionID)
, SummarizedCTE as ( 
select StudentID, OnlineExamID ,CourseID , CentreID , sum(Mark) as TotalMark from CTEQuery 
group by StudentID, OnlineExamID ,CourseID , CentreID)
select <new query involving joining SummarizedCTE with the "other table" referenced in your discussion>

Answer 2

例如

with demoCTE 
as
(
  select id from table1
) select * from demoCTE
    join table2
   on demoCTE.id= table2.id

Answer 3

您需要先创建CTE，然后在下一个SELECT语句中使用它。

WITH cteTest (Column1) AS 
(
    SELECT column1
      FROM table1
)

SELECT *
  FROM cteTest
  JOIN Table2
    ON cteTest.column1 = Table2.column1

如何将公用表表达式的结果集与sql server 2005中的其他现有表连接？

3 个答案: