mysql-MYSQL傳入值的語句求解

MYSQL傳入值的語句求解

ID = s1;
PASSWORD = s2;
NAME = s3;
s1,s2,s3是傳進來的參數，有具體值，但是以
sql = "insert into qq(ID,PASSWORD,NAME) values(ID,PASSWORD,NAME)";
st.executeUpdate(sql);
寫入數據庫，數據庫中的ID,PASSWORD,NAME都是空的，但是
System.out.println(ID);
System.out.println(PASSWORD);
System.out.println(NAME);這樣檢驗ID這些的值又是有的，求問為什麼寫入數據庫就為空了？

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,"數據庫連接失敗!","錯誤",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,"注冊失敗","錯誤",2);
        e.printStackTrace();
    }
}

}

最佳回答：

解決了，應該用 sql = "insert into qq(id,password,name) values ("+s1+","+s2+","+s3+")";