VB.NET中能不能对DATASET再用SQL语言

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可以筛选数据，但不能是标准的SQL语句：
Me.DsUserManager1.Tables(0).Select("id > 5 and id <20")
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1.筛选：
dataset.tables("tabname").select("id=1")'相当于SQL中WHERE后的条件内容

2.保存到哪？这倒是不知，可能开辟一个内存，也可能是一个临时区....
应该相当于从一个表中select
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Select函数返回一个DataRow()对象数组，可用循环方法加入数据集：

dim row as datarow
dim rows() as datarow=Me.DsUserManager1.Tables(0).Select("id > 5 and id <20")
if rows.length>0 then DsUserManager1.table(0).clear'重新导入筛选的数据
for each row in rows
DsUserManager1.table(0).ImportRow(row)
next

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ms-help://MS.MSDNQTR.2003FEB.2052/cpref/html/frlrfSystemDataDataTableClassSelectTopic.htm
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类似这样
OdbcCommand1.CommandText = "select * from xx"
                OdbcDataAdapter1.SelectCommand = OdbcCommand1
                OdbcDataAdapter1.Fill(dataset1, "xx")
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可以对dataset中的dataview进行筛选。例如：dataview1.rowFilter="Parent_id"=+Parent.id.tostring

dataview排序用dataview1.sort="Parent ASC"
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你要在Table中重新定义一次主键才行，如下：
Private Sub GetRowsByFilter()

    Dim customerTable As DataTable
    customerTable = new DataTable( "Customers" )

    ' Add columns
    customerTable.Columns.Add( "id", GetType(Integer) )
    customerTable.Columns.Add( "name", GetType(String) )

    ' Set PrimaryKey
    customerTable.Columns("id").Unique = true
    customerTable.PrimaryKey = new DataColumn() { customerTable.Columns("id") }

    ' add ten rows
    Dim id As Integer
    For id = 1 To 10
        customerTable.Rows.Add( _
            new object() { id, string.Format("customer{0}", id) } )
    Next id
    customerTable.AcceptChanges()

    ' add another ten rows
    For id = 11 To 20
        customerTable.Rows.Add( _
            new object() { id, string.Format("customer{0}", id) } )
    Next id

    Dim strExpr As String
    Dim strSort As String

    strExpr = "id > 5"
    ' Sort descending by CompanyName column.
    strSort = "name DESC"
    ' Use the Select method to find all rows matching the filter.
    Dim foundRows As DataRow() = _
        customerTable.Select( strExpr, strSort, DataViewRowState.Added )

    PrintRows( foundRows, "filtered rows")

    foundRows = customerTable.Select()
    PrintRows( foundRows, "all rows")
End Sub

Private Sub PrintRows( rows() As DataRow, label As String)
    Console.WriteLine( "/n{0}", label )
    If rows.Length <= 0 Then
        Console.WriteLine( "no rows found" )
        Exit Sub
    End If
    Dim r As DataRow
    Dim c As DataColumn
    For Each r In rows
        For Each c In r.Table.Columns
            Console.Write( "/t {0}", r(c) )
        Next c
        Console.WriteLine()
    Next r
End Sub