java - 我有一个 sql select 查询错误，不知道正确的语法是什么

Question

private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         
       String sql="select * from account where Username and Password=(?,?)"; //I think here is some error but dont know what it is

       try
       {
       stm=con.prepareStatement(sql);
       stm.setString(1,jTextField1.getText());
       stm.setString(2,jPasswordField1.getText());
       rs=stm.executeQuery();
       if(rs.next())
       {
       rs.close();
       stm.close();
       setVisible(false);
       Loading ob =new Loading();
       ob.setVisible(true);
       }
       else
       {
       JOptionPane.showMessageDialog(null,"Incorrect username and password");
       }
       }
       catch(SQLException exp)
       {
       JOptionPane.showMessageDialog(null, exp);
       }
       finally
       {
       try
       {
       rs.close();
       stm.close();
       }
       catch(SQLException exp)
       {
       exp.printStackTrace();
       }
       }


    }                                        

Answer 1

String sql="select * from account where Username and Password=(?,?)"; 

嗯，我不是 SQL 专家，但我认为它应该是:

String sql="select * from account where Username = ? and Password=?"; 

我希望您计划在每次遇到小问题时提出问题。 SQL 语法是什么你不能随便猜，所以你需要买本书或找教程。

也许是 JDBC Database Access可以为您提供一些一般信息。