如何在不重复数据的情况下在水晶报表中显示数据？

Question

我在使用左连接在水晶报表中显示数据时遇到问题，因为它复制了我的数据，即使我在sqlcommand中使用GROUP BY。

这是我的表格列表：

table 1: complaint

table 2: errordesc (error description)

这是我在水晶报告中的代码：

    Dim objConn As MySqlConnection
    Dim daT1, daT2 As MySqlDataAdapter
    Dim activecomp As DataSet
    Dim strConnection As String
    Dim strSQL As String

    strConnection = "server=localhost;user id=root;password=;database=ticketing_system;"
    objConn = New MySqlConnection(strConnection)
    objConn.Open()

    strSQL = "SELECT * FROM errordesc LEFT JOIN complaint ON errordesc.tran_no=complaint.tran_no WHERE errordesc.status='On-process' group by errordesc.err_id "
    daT1 = New MySqlDataAdapter(strSQL, objConn)
    activecomp = New DataSet
    daT1.Fill(activecomp, "comp")
    daT1.Fill(activecomp, "active")

    Dim rpt As New CrystalReport1
    rpt.SetDataSource(activecomp)
    CrystalReportViewer1.ReportSource = rpt

    objConn.Close()

我的出局是这样的：

它重复了我的errordesc.err_id，即使我把它归为一组。 :(请帮助，如果有人知道。提前谢谢......

Answer 1

我认为删除重复行的简单方法是更改​​strSQL：

strSQL = "SELECT DISTINCT * FROM errordesc LEFT JOIN "+
    "complaint ON errordesc.tran_no=complaint.tran_no "+
    "WHERE errordesc.status='On-process' group by errordesc.err_id "

Answer 2

oohh。我通过编写像这样的水晶报告解决了我自己的问题：

Dim objConn As MySqlConnection
    Dim daT1, daT2 As MySqlDataAdapter
    Dim activecomp As DataSet
    Dim strConnection As String
    Dim strSQL As String

    strConnection = "server=localhost;user id=root;password=;database=ticketing_system;"
    objConn = New MySqlConnection(strConnection)
    objConn.Open()


    strSQL = "SELECT * FROM errordesc WHERE errordesc.status='On-process' group by errordesc.err_id "
    daT1 = New MySqlDataAdapter(strSQL, objConn)
    activecomp = New DataSet
    daT1.Fill(activecomp, "errordesc")

    strSQL = "SELECT * FROM complaint left join errordesc on complaint.tran_no=errordesc.tran_no group by complaint.tran_no"
    daT2 = New MySqlDataAdapter(strSQL, objConn)
    daT2.Fill(activecomp, "complaint")

    Dim rpt As New CrystalReport1
    rpt.SetDataSource(activecomp)
    CrystalReportViewer1.ReportSource = rpt

    objConn.Close()