MYSQL传入值的语句求解

Question

ID = s1;
PASSWORD = s2;
NAME = s3;
s1,s2,s3是传进来的参数，有具体值，但是以
sql = "insert into qq(ID,PASSWORD,NAME) values(ID,PASSWORD,NAME)";
st.executeUpdate(sql);
写入数据库，数据库中的ID,PASSWORD,NAME都是空的，但是
System.out.println(ID);
System.out.println(PASSWORD);
System.out.println(NAME);这样检验ID这些的值又是有的，求问为什么写入数据库就为空了？

zhuce.yon(S1,S2,S3);

public class zhuce {

public static void yon(String s1, String s2, String s3)
{
    String ID = null;
    String PASSWORD = null;
    String NAME = null;

    ID = s1;
    PASSWORD = s2;
    NAME = s3;
    Connection con = null;
    String sql;
    Statement st = null;
    try {
        con = JDBC.getConnection();
    } catch (SQLException e) {
        // TODO Auto-generated catch block
        JOptionPane.showMessageDialog(null,"数据库连接失败!","错误",2);
        e.printStackTrace();
    }
    try {
        System.out.println(ID);
        System.out.println(PASSWORD);
        System.out.println(NAME);
        st = con.createStatement();
    } catch (SQLException e) {
        // TODO Auto-generated 
        e.printStackTrace();
    }
    sql = "insert into qq(ID,PASSWORD,NAME) values(ID,PASSWORD,NAME)";
    try {
        st.executeUpdate(sql);
    } catch (SQLException e) {
        // TODO Auto-generated catch block
        JOptionPane.showMessageDialog(null,"注册失败","错误",2);
        e.printStackTrace();
    }
}

}

Answer 1

解决了，应该用 sql = "insert into qq(id,password,name) values ("+s1+","+s2+","+s3+")";