MS Access 2007 中的多个联合语句中的嵌套错误

Posted 2023-05-07

【中文标题】MS Access 2007 中的多个联合语句中的嵌套错误

【英文标题】：Nested Error in multiple union statement in MS Access 2007

【发布时间】：2012-02-13 20:46:01

【问题描述】：

我收到一个错误 - '无法开始交易；已经嵌套了太多事务。当我使用 7 个联合语句进行查询时。如果我删除一个联合声明并将其设为 6，那么一切都会完美运行。解决此问题的任何帮助都将非常有价值。

谢谢！

我正在使用的表格：

School_TBL 由课程栏和学生栏组成。一个学生可以学习多门课程（因此它是一个多值领域）

SQL 语句如下：

    select 'John' as Student Name, Sum(IIf([CourseID]=1,1,0)) as Math, Sum(IIf([CourseID]=2,1,0)) AS English
    From School_TBL
    where (School_TBL.StudentID.value = 2 and School_TBL.CourseID.Value=1)
    GROUP BY School_TBL.StudentID.Value

    UNION ALL
    select 'Jane' as Student Name, Sum(IIf([CourseID]=1,1,0)) as Math, Sum(IIf([CourseID]=2,1,0)) AS English
    From School_TBL
    where (School_TBL.StudentID.value = 3 and School_TBL.CourseID.Value=1)
    GROUP BY School_TBL.StudentID.Value

    UNION ALL
    select 'Jim' as Student Name, Sum(IIf([CourseID]=1,1,0)) as Math, Sum(IIf([CourseID]=2,1,0)) AS English
    From School_TBL
    where (School_TBL.StudentID.value = 4 and School_TBL.CourseID.Value=1)
    GROUP BY School_TBL.StudentID.Value  

UNION ALL
    select 'Hank' as Student Name, Sum(IIf([CourseID]=1,1,0)) as Math, Sum(IIf([CourseID]=2,1,0)) AS English
    From School_TBL
    where (School_TBL.StudentID.value = 5 and School_TBL.CourseID.Value=1)
    GROUP BY School_TBL.StudentID.Value

    UNION ALL
    select 'Jay' as Student Name, Sum(IIf([CourseID]=1,1,0)) as Math, Sum(IIf([CourseID]=2,1,0)) AS English
    From School_TBL
    where (School_TBL.StudentID.value = 6 and School_TBL.CourseID.Value=1)
    GROUP BY School_TBL.StudentID.Value

    UNION ALL
    select 'Anna' as Student Name, Sum(IIf([CourseID]=1,1,0)) as Math, Sum(IIf([CourseID]=2,1,0)) AS English
    From School_TBL
    where (School_TBL.StudentID.value = 7 and School_TBL.CourseID.Value=1)
    GROUP BY School_TBL.StudentID.Value

    UNION ALL
    select 'Amy' as Student Name, Sum(IIf([CourseID]=1,1,0)) as Math, Sum(IIf([CourseID]=2,1,0)) AS English
    From School_TBL
    where (School_TBL.StudentID.value = 8 and School_TBL.CourseID.Value=1)
    GROUP BY School_TBL.StudentID.Value

    UNION ALL
    select 'Jason' as Student Name, Sum(IIf([CourseID]=1,1,0)) as Math, Sum(IIf([CourseID]=2,1,0)) AS English
    From School_TBL
    where (School_TBL.StudentID.value = 9 and School_TBL.CourseID.Value=1)
    GROUP BY School_TBL.StudentID.Value

【问题讨论】：

您似乎遇到了设计问题。最好从学校表中发布一些示例数据，并附上关于预期结果的说明。

【参考方案1】：

如果您还没有第二张表格，您需要保存学生详细信息。您只需要一个在该表上执行连接的 select 语句即可提取学生姓名

SELECT Student.studentName, Sum(IIf([CourseID]=1,1,0)) AS math, Sum(IIf([CourseID]=2,1,0)) AS english
FROM school_tbl INNER JOIN Student ON school_tbl.studentId = Student.Studentid
GROUP BY Student.studentName;