How to query and insert into mysql.

According to my application, I need to copy some records from a table into another table in mysql. For example, I have two tables, t_imginfo and t_result. Both two tables have some structure.The primary key of t_imginfo is id. I want copy some records with specified .id into t_result. MY code is like

      sqlquery = sprintf('insert into t_result (select * from t_imginfo where id = %d)',30);
      curor = exec(conn, sqlquery);
      curor = fetch(curor);

After the code is executed, nothing changed. What should I do to meet my requirement?