多折线图

我一直在尝试制作从数据库中提取数据的多线图。为了做到这一点，我编写了以下代码来填充图表：

    SqlConnection con1 = new SqlConnection();
    con1.ConnectionString = ConfigurationManager.ConnectionStrings["Removed"].ToString();
    SqlCommand cmd1 = new SqlCommand("SELECT YEAR(Start_Date) AS Year, Month(Start_Date) As Month, Cost, Utility_Type FROM import_Utilities WHERE YEAR(Start_Date) = 2011  AND Utility_Type = 'Water'");
    cmd1.Connection = con1;
    con1.Open();

    SqlDataAdapter da1 = new SqlDataAdapter(cmd1);
    DataTable dt1 = new DataTable();
    da1.Fill(dt1);
    Chart1.DataSource = dt1;

    Chart1.Series["Series2"].XValueMember = "Month";
    Chart1.Series["Series2"].YValueMembers = "Cost";
    Chart1.Legends.Add(new Legend("Default") { Docking = Docking.Right });


    Chart1.DataBind();
    con1.Close();

    SqlConnection con = new SqlConnection();
    con.ConnectionString = ConfigurationManager.ConnectionStrings["Removed"].ToString();
    con.Open();
    SqlCommand cmd = new SqlCommand("SELECT YEAR(Start_Date) AS Year, Month(Start_Date) As Month, Cost, Utility_Type FROM import_Utilities WHERE YEAR(Start_Date) = 2012 AND Utility_Type = 'Water'");
    cmd.Connection = con;
    SqlDataAdapter da = new SqlDataAdapter(cmd);
    DataTable dt = new DataTable();
    da.Fill(dt);
    Chart1.DataSource = dt;
    Chart1.Series["2010"].XValueMember = "Month";
    Chart1.Series["2010"].YValueMembers = "Cost";

    Chart1.DataBind();
    con.Close();

该代码有效，除了它具有两个数据源之外，因此仅底部sqlconnection被填充到图表中。我不知道如何解决此问题，我想他们是这样做的更好方法，但我很茫然。

更新：

在下面的例子中，我最终使用数据透视表sql创建了一个表（参见图片）。然后，我将代码更新为以下内容：

 SqlCommand cmd = new SqlCommand("SELECT * FROM ( SELECT YEAR(Start_Date), CASE MONTH(Start_Date) WHEN 1 THEN 'January' WHEN 2 THEN 'February' WHEN 3 THEN 'March' WHEN 4 THEN 'April' WHEN 5 THEN 'May' WHEN 6 THEN 'June' WHEN 7 THEN 'July' WHEN 8 THEN 'August' WHEN 9 THEN 'September'WHEN 10 THEN 'October' WHEN 11 THEN 'November' WHEN 12 THEN 'December' END as [Month], [Cost] FROM [HousingAccountingReports].[dbo].[import_Utilities] Where [Building] = 'Building B' AND [Utility_Type] = 'Electric') TableDate PIVOT (SUM([Cost]) FOR [Month] IN ([January],[February],[March],[April],[May],[June],[July],[August],[September],[October],[November],[December] )) PivotTable");
    cmd.Connection = con;
    SqlDataAdapter da = new SqlDataAdapter(cmd);
    DataTable dt = new DataTable();
    da.Fill(dt);
    Chart3.DataSource = dt;
    Chart3.Series["Series1"].XValueMember = "Month";
    Chart3.Series["Series1"].YValueMembers = "2010";
    Chart3.Series["Series2"].XValueMember = "Month";
    Chart3.Series["Series2"].YValueMembers = "2011";
    Chart3.Series["Series3"].XValueMember = "Month";
    Chart3.Series["Series3"].YValueMembers = "2012";
    Chart3.DataBind();`

当我运行页面时，错误提示找不到“月份”列。如果我添加：
dt.Columns.Add（“ Month”）; dt.Columns.Add（“ Year”）;`找不到2010，如何正确引导我的图表；他们是我的枢轴SQL问题吗？