if (!IsPostBack)
        {
            this.ReportViewer1.LocalReport.SubreportProcessing += new SubreportProcessingEventHandler(SubreportProcessingEventHandler);
            string strConn = SqlHelper.t6;
            SqlConnection conn = new SqlConnection(strConn);
            SqlCommand selcmd = new SqlCommand();
            selcmd.Connection = conn;
            selcmd.CommandText = "select ccuscode from customer";
            SqlDataAdapter da = new SqlDataAdapter();
            da.SelectCommand = selcmd;
            DataSet ds = new DataSet();
            ds.Clear();
            da.Fill(ds, "rewq");
            ReportViewer1.LocalReport.ReportPath = ".\\report.rdlc";
            ReportViewer1.Visible = true;
            ReportDataSource reSource = new ReportDataSource("DataSet2", ds.Tables[0]);
            ReportViewer1.LocalReport.DataSources.Clear();
            ReportViewer1.LocalReport.EnableExternalImages = true;
            ReportViewer1.LocalReport.EnableHyperlinks = true;
            ReportViewer1.LocalReport.DataSources.Add(reSource);
            ReportViewer1.LocalReport.Refresh();
        }
    }




    void SubreportProcessingEventHandler(object sender, SubreportProcessingEventArgs e)
    {
        //注意dataset2必须和你子报表所引用的table 一致
        string strConn = SqlHelper.t6;
        SqlConnection conn = new SqlConnection(strConn);
        SqlCommand selcmd = new SqlCommand();
        selcmd.Connection = conn;
        selcmd.CommandText = "select ccusname from customer";
        SqlDataAdapter da = new SqlDataAdapter();
        da.SelectCommand = selcmd;
        DataSet ds = new DataSet();
        ds.Clear();
        da.Fill(ds, "rewq");
        e.DataSources.Add(new ReportDataSource("DataSet1", ds.Tables[0]));
    }

以上是代码，我就测试下，customer是张客户表，一个是现实客户编码，子报表现实相应的客户名称。 数据将近有几千条。内部的参数我都设置好了，如果主表加上where语句，显示一条记录可以正常显示，而且子报表正常显示相对应额客户名称。但是去掉where的话，统计的话无法显示出来，等了20分钟显示数据库超时。请问到底什么问题？