机房收费系统之组合查询

如果提到组合查询大家映入眼帘的是什么，当我刚刚接触到她的时候感觉她很难，因为在做组合查询的时候好多同学都做出来了，做出来以后都说很难，她如“犹抱琵琶半遮面”的美女，让我对她充满了好奇，在师傅第一次验收之后当时我确实做出来了，感觉还洋洋得意，但是当师傅验收的时候，我才注意到一个问题就是我的组合查询并没有做到精确查询当检验到数字的时候，她根本就没有反应，比如卡号控制在0到100以内的时候我才发现我原来并没有把所有的数据进行限制，大于100的数字都出来了，但是我当时并没有注意到这个问题，后来我看了十期连江伟师兄的博客才认识到这个问题，于是对我的代码做到了一个修改，问题出现在我们写的SQL语句根本就不对，我们把数字当成了字符所以特没有办法查出来。

  If Combo7.Text = "" Then        If IsNumeric(Text1.Text) Then        txtSQL = "select * from Line_Info where " & Trim(FileName(Combo1.Text)) & Trim(Combo4.Text) & "" & Text1.Text & ""    Else    txtSQL = "select * from Line_Info where " & Trim(FileName(Combo1.Text)) & Trim(Combo4.Text) & "'" & Trim(Text1.Text) & "'"    End If'    txtSQL = "select * from student_Info where " & Trim(FileName(Combo1.Text)) & "" & Trim(Combo4.Text) & "'" & Trim(Text1.Text) & "'"            Else    If Combo8.Text = "" Then    If IsNumeric(Text1.Text) And IsNumeric(Text2.Text) Then    txtSQL = "select * from Line_Info where " & Trim(FileName(Combo1.Text)) & Trim(Combo4.Text) & "" & Text1.Text & "" & Trim(FileName(Combo7.Text)) & " " & Trim(FileName(Combo2.Text)) & Trim(Combo5.Text) & "" & Text2.Text & ""    ElseIf IsNumeric(Text1.Text) And Not IsNumeric(Text2.Text) Then    txtSQL = "select * from Line_Info where " & Trim(FileName(Combo1.Text)) & Trim(Combo4.Text) & "" & Text1.Text & "" & Trim(FileName(Combo7.Text)) & " " & Trim(FileName(Combo2.Text)) & Trim(Combo5.Text) & "'" & Trim(Text2.Text) & "'"    ElseIf Not IsNumeric(Text1.Text) And IsNumeric(Text2.Text) Then    txtSQL = "select * from Line_Info where " & Trim(FileName(Combo1.Text)) & Trim(Combo4.Text) & "'" & Trim(Text1.Text) & "'" & Trim(FileName(Combo7.Text)) & " " & Trim(FileName(Combo2.Text)) & Trim(Combo5.Text) & "" & Text2.Text & ""    Else     txtSQL = "select * from Line_Info where " & Trim(FileName(Combo1.Text)) & Trim(Combo4.Text) & "'" & Trim(Text1.Text) & "'" & Trim(FileName(Combo7.Text)) & " " & Trim(FileName(Combo2.Text)) & Trim(Combo5.Text) & "'" & Trim(Text2.Text) & "'"     End If            Else       If IsNumeric(Text1.Text) And IsNumeric(Text2.Text) And IsNumeric(Text3.Text) Then       txtSQL = "select * from Line_Info where " & Trim(FileName(Combo1.Text)) & Trim(Combo4.Text) & "" & Text1.Text & "" & Trim(FileName(Combo7.Text)) & " " & Trim(FileName(Combo2.Text)) & Trim(Combo5.Text) & "" & Text2.Text & "" & Trim(FileName(Combo8.Text)) & " " & Trim(FileName(Combo3.Text)) & Trim(Combo6.Text) & "" & Text3.Text & ""       ElseIf IsNumeric(Text1.Text) And IsNumeric(Text2.Text) And Not IsNumeric(Text3.Text) Then       txtSQL = "select * from Line_Info where " & Trim(FileName(Combo1.Text)) & Trim(Combo4.Text) & "" & Text1.Text & "" & Trim(FileName(Combo7.Text)) & " " & Trim(FileName(Combo2.Text)) & Trim(Combo5.Text) & "" & Text2.Text & "" & Trim(FileName(Combo8.Text)) & " " & Trim(FileName(Combo3.Text)) & Trim(Combo6.Text) & "'" & Trim(Text3.Text) & "'"       ElseIf IsNumeric(Text1.Text) And Not IsNumeric(Text2.Text) And IsNumeric(Text3.Text) Then       txtSQL = "select * from Line_Info where " & Trim(FileName(Combo1.Text)) & Trim(Combo4.Text) & "" & Text1.Text & "" & Trim(FileName(Combo7.Text)) & " " & Trim(FileName(Combo2.Text)) & Trim(Combo5.Text) & "'" & Trim(Text2.Text) & "'" & Trim(FileName(Combo8.Text)) & " " & Trim(FileName(Combo3.Text)) & Trim(Combo6.Text) & "" & Text3.Text & ""       ElseIf IsNumeric(Text1.Text) And Not IsNumeric(Text2.Text) And Not IsNumeric(Text3.Text) Then       txtSQL = "select * from Line_Info where " & Trim(FileName(Combo1.Text)) & Trim(Combo4.Text) & "" & Text1.Text & "" & Trim(FileName(Combo7.Text)) & " " & Trim(FileName(Combo2.Text)) & Trim(Combo5.Text) & "'" & Trim(Text2.Text) & "'" & Trim(FileName(Combo8.Text)) & " " & Trim(FileName(Combo3.Text)) & Trim(Combo6.Text) & "'" & Trim(Text3.Text) & "'"       ElseIf Not IsNumeric(Text1.Text) And IsNumeric(Text2.Text) And IsNumeric(Text3.Text) Then       txtSQL = "select * from Line_Info where " & Trim(FileName(Combo1.Text)) & Trim(Combo4.Text) & "'" & Trim(Text1.Text) & "'" & Trim(FileName(Combo7.Text)) & " " & Trim(FileName(Combo2.Text)) & Trim(Combo5.Text) & "" & Text2.Text & "" & Trim(FileName(Combo8.Text)) & " " & Trim(FileName(Combo3.Text)) & Trim(Combo6.Text) & "" & Text3.Text & ""       ElseIf Not IsNumeric(Text1.Text) And Not IsNumeric(Text2.Text) And IsNumeric(Text3.Text) Then       txtSQL = "select * from Line_Info where " & Trim(FileName(Combo1.Text)) & Trim(Combo4.Text) & "'" & Trim(Text1.Text) & "'" & Trim(FileName(Combo7.Text)) & " " & Trim(FileName(Combo2.Text)) & Trim(Combo5.Text) & "'" & Trim(Text2.Text) & "'" & Trim(FileName(Combo8.Text)) & " " & Trim(FileName(Combo3.Text)) & Trim(Combo6.Text) & "" & Text3.Text & ""       ElseIf Not IsNumeric(Text1.Text) And IsNumeric(Text2.Text) And Not IsNumeric(Text3.Text) Then       txtSQL = "select * from Line_Info where " & Trim(FileName(Combo1.Text)) & Trim(Combo4.Text) & "'" & Trim(Text1.Text) & "'" & Trim(FileName(Combo7.Text)) & " " & Trim(FileName(Combo2.Text)) & Trim(Combo5.Text) & "" & Text2.Text & "" & Trim(FileName(Combo8.Text)) & " " & Trim(FileName(Combo3.Text)) & Trim(Combo6.Text) & "'" & Trim(Text3.Text) & "'"       Else                     txtSQL = "select * from Line_Info where " & Trim(FileName(Combo1.Text)) & Trim(Combo4.Text) & "'" & Trim(Text1.Text) & "'" & Trim(FileName(Combo7.Text)) & " " & Trim(FileName(Combo2.Text)) & Trim(Combo5.Text) & "'" & Trim(Text2.Text) & "'" & Trim(FileName(Combo8.Text)) & " " & Trim(FileName(Combo3.Text)) & Trim(Combo6.Text) & "'" & Trim(Text3.Text) & "'"       End If           End If End If