java - sql中一列所有值的总和

Question

我需要获取一列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，但出现错误。 - 列名 Sum(Price) 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.

Answer 1

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);

我不知道值是否正确转换。该值是某种数字。也许你想要:

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