Question

我真的很累。我有这个查询它非常适合我的Sql服务器数据库但是当我把它与我的MS Access数据库放在一起时我有一个错误（索引（零基数）必须大于或等于零并且小于参数列表的大小）。 Sql server查询：

Dim sql As String = String.Format(" SELECT TOP {0} ID1,Team1,Team2,Team3 FROM (SELECT ROW_NUMBER() OVER(ORDER BY newid() ASC) AS F1, ID1, Team1, Team2 FROM Table1 ) as t1 INNER JOIN (SELECT ROW_NUMBER() OVER(ORDER BY newid() ASC) AS F1,Team3 FROM Table2 )  as t2 on t1.f1 = t2.f1", rows)

MS Access查询：

Dim sql As String = String.Format(" SELECT TOP (0) ID1,Team1,Team2,Team3 FROM (SELECT ROW_NUMBER() OVER(ORDER BY {" & Guid.NewGuid().ToString & "} ASC) AS F1,ID1,Team1,Team2 from Table1) as t1 INNER JOIN (SELECT ROW_NUMBER() OVER(ORDER BY {" & Guid.NewGuid().ToString & "} ASC) AS F1, Team3 FROM Table2 ) as t2 on t1.f1 = t2.f1 ", rows)

我在Form1中的代码加载：

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    Conn_Randomize()
    InfoCommand = New OleDbCommand("SELECT * FROM Table1 ORDER BY Team2", Conn_Randomize)
    InfoAdapter = New OleDbDataAdapter()
    InfoAdapter.SelectCommand = InfoCommand
    InfoTable = New DataTable()
    InfoAdapter.Fill(InfoTable)
    DataGridView1.DataSource = InfoTable
End Sub

我希望在DataGridView2中使用NumericupDown1和2显示输入行数和列数的代码并随机化

    Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
    Conn_Randomize()
    Dim rows As Integer
    If Not Integer.TryParse(NumericUpDown1.Value, rows) Then
        MsgBox("NUMBER NOT AVAILABLE", MsgBoxStyle.Critical + MsgBoxStyle.OkOnly, "Error")
        NumericUpDown1.Value = ""
        NumericUpDown1.Focus()
        Exit Sub
    End If
    If NumericUpDown2.Value = 2 Then
        Dim sql As String = String.Format("SELECT Top {0} ID1, Team1, Team2 FROM Table1  ORDER BY RND(-(100000*ID1)*Time())", rows)
        InfoCommand = New OleDbCommand(sql, Conn_Randomize)
        InfoAdapter = New OleDbDataAdapter()
        InfoAdapter.SelectCommand = InfoCommand
        InfoTable = New DataTable()
        InfoAdapter.Fill(InfoTable)
        DataGridView2.DataSource = InfoTable
    End If
    If NumericUpDown2.Value = 3 Then
        Dim sql As String = String.Format(" SELECT TOP {0} ID1,Team1,Team2,Team3 FROM (SELECT ROW_NUMBER() OVER(ORDER BY {" & Guid.NewGuid().ToString & "} ASC) AS F1,ID1,Team1,Team2 from Table1) as t1 INNER JOIN (SELECT ROW_NUMBER() OVER(ORDER BY {" & Guid.NewGuid().ToString & "} ASC) AS F1, Team3 FROM Table2 ) as t2 on t1.f1 = t2.f1 ", rows)
        InfoCommand = New OleDbCommand(sql, Conn_Randomize)
        InfoAdapter = New OleDbDataAdapter()
        InfoAdapter.SelectCommand = InfoCommand
        InfoTable = New DataTable()
        InfoAdapter.Fill(InfoTable)
        DataGridView2.DataSource = InfoTable
    End If
End Sub

Answer 1

在执行第二个代码段后，您是否真正了解了sql包含的内容？它有意义吗？

第一个代码片段使用的是newid，这是一个T-SQL函数，这意味着数据库将为每一行生成一个新的uniqueidentifier并使用它们对数据进行排序。第二个代码片段怎么能做同等的事情呢？它只在VB代码中调用NewGuid一次，并将结果连接到SQL代码中。您很幸运，这甚至是有效的语法，但结果并不是每条记录都有不同的值要排序。

您需要数据库为每个可用作排序键的记录生成值，并且在Access SQL中生成随机数的方法是Rnd。我以为你那天前已经在使用了。

另外，虽然我还没有检查过，但我也不确定Access中是否支持ROW_NUMBER。很久以前它就没有被添加到SQL Server中。

疯狂随机化MS Access查询

1 个答案: