Question

我有这个SQL查询

cmd.CommandText = "SELECT [tblStudent]![LastName] & ', ' & [tblStudent]![FirstName] & ' ' & [tblStudent]![MiddleName] AS FullName," & _
" tblGrade.FirstGrading, tblGrade.SecondGrading, tblGrade.ThirdGrading, tblGrade.FourthGrading," & _
" Avg(b.GradeValue) AS AverageGrade" & _
" FROM ((((tblGrade INNER JOIN tblEnrolment ON tblGrade.EnrolmentID=tblEnrolment.EnrolmentID)" & _
    " INNER JOIN tblStudent ON tblStudent.StudentID=tblEnrolment.StudentID)" & _
    " INNER JOIN tblSubjectOffering ON tblSubjectOffering.SubjectOfferingID=tblGrade.SubjectOfferingID)" & _
    " INNER JOIN tblSubject ON tblSubject.SubjectID=tblSubjectOffering.SubjectID)" & _
    " INNER JOIN tblSection ON tblSection.SectionID=tblSubjectOffering.SectionID" & _
" WHERE tblSection.SectionTitle='" & s(0) & "' AND tblSubject.SubjectID='" + s2(0) + "'" & _
" GROUP BY [tblStudent]![LastName] & ', ' & [tblStudent]![FirstName] & ' ' & [tblStudent]![MiddleName], tblGrade.FirstGrading, tblGrade.SecondGrading, tblGrade.ThirdGrading, tblGrade.FourthGrading" & _
" ORDER BY [tblStudent]![LastName] & ', ' & [tblStudent]![FirstName] & ' ' & [tblStudent]![MiddleName]"

这段代码给了我一个运行时错误“没有一个或多个必需参数的值”。

Answer 1

我的预感是Access认为b.GradeValue是参数，因为b没有表名或别名：

Avg(b.GradeValue) AS AverageGrade

我建议您Debug.Print完成SELECT语句，或将其写入文本文件，然后在Access查询设计器中将其作为新查询进行测试。当它要求您提供参数值时，它还会显示“name”，无论它认为是什么参数。

Answer 2

很难仅使用SQL语句提供建议，与其他代码和对象脱离上下文。

目前，我看到两个主要的潜在问题。首先是你有Avg(b.GradeValue)但是在命令的其他地方没有引用b表。为此，您需要删除b或确保引用有效。

其次，您有两个变量s()和s2()可能会返回无效或空数据。您可能希望调试此步骤并在继续执行之前检查每个保留的值，然后将问题解决到代码的其他部分（如果一个是坏的）。

无一个或多个必需参数的值

2 个答案: