com.microsoft.sqlserver.jdbc.SQLServerexception：'='附近的语法不正确

Question

我猜第一行出现错误！ 请帮我解决它。 我基本上是想通过前端执行查询

try {            
        ResultSet rs=st.executeQuery("select *from Login Username ='"+username+"' and Password  '"+password+"'");
        rs.last();
        int counter = rs.getRow();
        if (counter==1){
            JOptionPane.showMessageDialog(null,"Username and Password Correct","Username and Password Correct",JOptionPane.INFORMATION_MESSAGE);

            this.setVisible(false);
            new Menu().setVisible(true);
            hide();
            }else{
            jt_username.setText("");
            jp_password.setText("");
            JOptionPane.showMessageDialog(null,"Error","Username and Password Incorrect",JOptionPane.INFORMATION_MESSAGE);            
        }
    }
    catch (SQLException ex) {
        JOptionPane.showMessageDialog(null, ex);
    }

Answer 1

您的SQL缺少WHERE关键字。 尝试以下尺寸：

ResultSet rs=st.executeQuery("select * from Login WHERE Username ='"+username+"' and Password=  '"+password+"'");