该来的总会来的！！！！组合查询就这么悄无声息的到了，

组合查询 最重要的就是运用数据的概念：

   Dim i As integer
    For i = 0 To 2
        With Combo1(i)
          	  .AddItem "卡号"
          	  .AddItem "学号"
          	  .AddItem "姓名"
          	 	 .AddItem "性别"
          	  .AddItem "日期"
           	 .AddItem "时间"
          	  .AddItem "机器名"
        End With
    Next i

还要注意一些细节问题：

Dim i As Integer
    i = Index
  If Combo1(i).Text = "姓名" Or Combo1(i).Text = "性别" Then  '防止出现姓名 备注等大于小于的情况
        Combo2(i).Clear
        Combo2(i).AddItem "="
        Combo2(i).AddItem "<>"
        Else
      Combo2(i).Clear      '每次切换完都要清空一下 防止重复叠加选项的情况出现
         Combo2(i).AddItem "="
         Combo2(i).AddItem "<"
         Combo2(i).AddItem ">"
         Combo2(i).AddItem "<>"
 End If

不要忘记日期控件：

For i = 0 To 2
If Combo1(i).Text = "日期" Then
            DTPicker1(i).Format = dtpShortDate
            DTPicker1(i).Visible = True
            Text1(i).Visible = False
        Else
    If Combo1(i).Text = "时间" Then
            DTPicker1(i).Format = dtpTime
            DTPicker1(i).Visible = True
            Text1(i).Visible = False
        Else
            DTPicker1(i).Visible = False
            Text1(i).Visible = True
        If Combo1(i).Text = "卡号" Or Combo1(i).Text = "学号" Or Combo1(i).Text = "姓名" Or Combo1(i).Text = "机器名" Or Combo1(i).Text = "性别" Then
            DTPicker1(i).Visible = False
            Text1(i).Visible = True
        End If
  End If
End If
  Next i

  '这里日期是有多种格式的 dtpicker的fromat属性提供了好几种日期格式
  'format=0-dtpLongDate：格式是2018年12月13日
  'format=1-dtpShortDate：格式是2018/12/13
  'format=2-dtpTime：格式是0:00:00，这个时候是时间，不是日期
  'Format=3-dtpCustom，这个时候可以自定义格式，比如 
    dtpicker1.CustomFormat=Format("yy MM dd")

窗体准备完毕剩下的就是查询了

 	Dim txtSQLlin As String
    Dim MsgText As String
    Dim Mrclin As ADODB.Recordset
    Dim i As Integer
        
        For i = 0 To 2
            If DTPicker1(i).Visible = True Then  '查询的时候将dipicker中的日期赋值给文本框   将条件字段名转换成相对应的数据库字段名字符
                Text1(i).Text = DTPicker1(i).Value
            End If
        Next i
   
    If Not Testtxt(Combo1(0).Text) Or Not Testtxt(Combo4(0).Text) Or Not Testtxt(Text1(0).Text) Then
        MsgBox "请输入第一行查询条件的内容", 48, "提示"
        Combo1(0).SetFocus
        Exit Sub
    End If
    
    txtSQLlin = "select * from line_info where "
    txtSQLlin = txtSQLlin & Trim(Fieldname(Combo1(0).Text)) & Trim(Combo4(0).Text) & "'" & Trim(Text1(0).Text) & "'"
    
    If Not Combo7(0).Text = "" Then  '如果选择框不是空值
    
    '判断第二行是否输入
    If Not Testtxt(Combo1(1).Text) Or Not Testtxt(Combo4(1).Text) Or Not Testtxt(Text1(1).Text) Then
        MsgBox "请输入第二行条件内容", 48, "提示"
        Combo1(1).SetFocus
        Exit Sub
    End If
            
             txtSQLlin = txtSQLlin & " " & RelationName(Trim(Combo7(0).Text)) & " " & Fieldname(Combo1(1).Text) & " " & Trim(Combo4(1).Text) & "'" & Trim(Text1(1).Text) & " '"
                 
                 End If
    If Not Combo7(1).Text = "" Then
    '判断第三行是否输入
        If Not Testtxt(Combo1(2).Text) Or Not Testtxt(Combo4(2).Text) Or Not Testtxt(Text1(2).Text) Then
            MsgBox "请输入第三行查询条件的内容", 48, "提示"
            Combo1(2).SetFocus
            Exit Sub
        Else
                
            txtSQLlin = txtSQLlin & RelationName(Trim(Combo7(1).Text)) & " " & Fieldname(Combo1(2).Text) & Trim(Combo4(2).Text) & "'" & Trim(Text1(2).Text) & "'"
         '        Txtsql = Txtsql & RelationName(Combo3(1).Text) & " " & Fieldname(Combo1(2).Text) & Combo2(2).Text & "'" & Trim(Text1(2).Text) & "'"

        End If
    End If
    
    Set Mrclin = ExecuteSQL(txtSQLlin, MsgText)
    With MSFlexGrid1
                    .Rows = 1  '内容在当前单元格的水平和垂直居中对齐
                    .CellAlignment = 4  '内容在当前列居中对齐
                    .CellAlignment = 4
                    .TextMatrix(0, 0) = "卡号"
                    .TextMatrix(0, 1) = "姓名"
                    .TextMatrix(0, 2) = "上机日期"
                    .TextMatrix(0, 3) = "上机时间"
                    .TextMatrix(0, 4) = "下机日期"
                    .TextMatrix(0, 5) = "下机时间"
                    .TextMatrix(0, 6) = "消费金额"
                    .TextMatrix(0, 7) = "余额"
                    .TextMatrix(0, 8) = "备注"
                    Do While Not Mrclin.EOF
                                        .Rows = .Rows + 1
                                        .CellAlignment = 4
                                        .CellAlignment = 4
                                        .TextMatrix(.Rows - 1, 0) = Trim(Mrclin.Fields(1))
                                        .TextMatrix(.Rows - 1, 1) = Trim(Mrclin.Fields(3))
                                        .TextMatrix(.Rows - 1, 2) = Trim(Mrclin.Fields(6))
                                        .TextMatrix(.Rows - 1, 3) = Trim(Mrclin.Fields(7))
                                        .TextMatrix(.Rows - 1, 4) = Trim(Mrclin.Fields(8)) & ""
                                        .TextMatrix(.Rows - 1, 5) = Trim(Mrclin.Fields(9)) & ""
                                        .TextMatrix(.Rows - 1, 6) = Trim(Mrclin.Fields(11))
                                        .TextMatrix(.Rows - 1, 7) = Trim(Mrclin.Fields(12))
                                        .TextMatrix(.Rows - 1, 8) = Trim(Mrclin.Fields(13))                 
                    Mrclin.MoveNext
                Loop
                Call AdjustColWidth(cmdinquir, MSFlexGrid1)
                   End With
                   If Mrclin.RecordCount = 0 Then
                   MsgBox "没有您要查询的信息", 48, "提示"
                   Combo1(0).SetFocus                  
                End If
           Mrclin.Close  
End Sub

这个组合查询要好好理解一些 写的时候一定要细心 遇到错误 多用断点 监事窗口 立即窗口等工具检查问题所在，然后一个会了 其他的就没什么问题的