Java sql中一列的所有值之和

我需要得到一列中所有值的总和，并将其放入文本字段中。我尝试了下面的代码，但出现了一个错误。-列名称总和（价格）无效

     String sql="Select Sum(Price) from sold";
                              pst=con.prepareStatement(sql);
                              rs=pst.executeQuery();
                              if(rs.next()){
                                  String sum = rs.getString("Sum(Price)");
                                  textField_2.setText(sum);

com.microsoft.sqlserver.jdbc.SQLServerException: The column name Sum(Price) is not valid.

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为计算列使用别名

Select Sum(Price) as sum_price from sold
...
String sum = rs.getString("sum_price");
textField_2.setText(sum);

---

为计算列使用别名

Select Sum(Price) as sum_price from sold
...
String sum = rs.getString("sum_price");
textField_2.setText(sum);

使用别名：

 String sql="Select Sum(Price) as sumprice from sold";
                          pst=con.prepareStatement(sql);
                          rs=pst.executeQuery();
                          if(rs.next()){
                              String sum = rs.getString("sumprice");
                              textField_2.setText(sum);

我不知道这些值转换是否正确。该值是某种类型的数字。也许你想要：

 String sql="Select cast(Sum(Price) as varchar(255)) as sumprice from sold";

使用别名：

 String sql="Select Sum(Price) as sumprice from sold";
                          pst=con.prepareStatement(sql);
                          rs=pst.executeQuery();
                          if(rs.next()){
                              String sum = rs.getString("sumprice");
                              textField_2.setText(sum);

我不知道这些值转换是否正确。该值是某种类型的数字。也许你想要：

 String sql="Select cast(Sum(Price) as varchar(255)) as sumprice from sold";

---

使用将序号列编号作为聚合结果的重载默认为无名：

---

rs.getString（1）

使用默认情况下不命名的重载，该重载将序号列作为聚合的结果：

rs.getString（1）

试试这个

        int sum = 0;
        Statement st = conn.createStatement();
        ResultSet res = st.executeQuery("SELECT SUM(price) FROM sold");
        while (res.next()) {
        int c = res.getInt(1);
        sum = sum + c;

        String str = Integer.toString(sum);
        textField_2.setText(str);

这会起作用的

试试这个

        int sum = 0;
        Statement st = conn.createStatement();
        ResultSet res = st.executeQuery("SELECT SUM(price) FROM sold");
        while (res.next()) {
        int c = res.getInt(1);
        sum = sum + c;

        String str = Integer.toString(sum);
        textField_2.setText(str);

这会奏效的