c# - 为什么我无法通过对表执行第二个查询来将第二个结果添加到列表框？ SQL

Question

我遇到这个错误是因为我想通过对每个整数进行计数来打印出同一电影名称中的所有 5 个不同的评级整数。第一个查询执行得非常完美，但为什么由于出现如下错误而无法使第二个查询正常工作？

错误:{“列‘RatingNum2’不属于表 Table。”}

   private void EachRating_Click(object sender, EventArgs e)
    {
        string filename, connectionInfo;
        SqlConnection db;

        this.listBox1.Items.Clear();

        filename = "netflix.mdf";

        connectionInfo = String.Format(@"Data Source=(LocalDB)\v11.0;AttachDbFilename=
        |DataDirectory|\{0};Integrated Security=True;", filename);

        string moviename = this.textBox1.Text;
        moviename = moviename.Replace("'", "''");

        string five = "5";
        string four = "4";

        db = new SqlConnection(connectionInfo);
        db.Open();

        SqlCommand cmd = new SqlCommand();
        cmd.Connection = db;

        cmd.CommandText = string.Format(
            @"
                SELECT MovieName, RatingNum1 FROM Movies
                INNER JOIN
                (
                SELECT MovieID, Count(Rating) as RatingNum1 FROM Reviews
                WHERE Rating = 5
                GROUP BY MovieID
                )TEMP
                ON TEMP.MovieID = Movies.MovieID
                WHERE MovieName = '{0}';", moviename);

        SqlDataAdapter adapter = new SqlDataAdapter(cmd);
        DataSet ds = new DataSet();
        adapter.Fill(ds);

        DataTable dt = ds.Tables["TABLE"];

        foreach (DataRow row in dt.Rows)
        {
            string msg = string.Format("{0}: {1}",
            five.ToString(),
            row["RatingNum1"].ToString());

            this.listBox1.Items.Add(msg);
        }

        SqlCommand cmd2 = new SqlCommand();
        cmd2.Connection = db;

        cmd2.CommandText = string.Format(
            @"
              SELECT MovieName, RatingNum2 FROM Movies
              INNER JOIN
              (
              SELECT MovieID, Count(Rating) as RatingNum2 FROM Reviews
              WHERE Rating = 4
              GROUP BY MovieID
              )TEMP
              ON TEMP.MovieID = Movies.MovieID
              WHERE MovieName = '{0}'", moviename);

        SqlDataAdapter adapter2 = new SqlDataAdapter(cmd2);
        DataSet ds2 = new DataSet();
        adapter.Fill(ds2);

        DataTable dt2 = ds2.Tables["TABLE"];

        foreach (DataRow row2 in dt2.Rows)
        {
            string msg = string.Format("{0}: {1}",
            four.ToString(),
            row2["RatingNum2"].ToString()); //gets the error

            this.listBox1.Items.Add(msg);
        }

Answer 1

您正在使用第一个适配器填充第二个数据集，因此数据表无法找到“RatingNum2”列。

adapter.Fill(ds2);

应该是

adapter2.Fill(ds2);