"INSERT INTO sed_forum_posts (fp_id,fp_topicid,fp_sectionid,fp_posterid,fp_post ername,fp_creation,fp_updated,fp_updater ,fp_text ,fp_posterip )
VALUES ('".$q."','".$q."','1','1','Mustafa YILMAZ','".time()."','".time()."','0','$msg','127. 0.0.1');" );
Bu sorguyu suna benzer olarak cevirebilirsin.
"INSERT INTO sed_forum_posts ((select max(id) from sed_forum_topics ) + 1),(select max(id) from sed_forum_topics ) + 1),fp_sectionid,fp_posterid,fp_postername,fp_creat ion,fp_updated,fp_updater ,fp_text ,fp_posterip )
VALUES ('".$q."','".$q."','1','1','Mustafa YILMAZ','".time()."','".time()."','0','$msg','127. 0.0.1');" );

gibi
yani ft_id yi basacagin yere oteki tablodaki max id yi alip bir arttiriyorsun. Bu olur boyle.
syntax hatasi verebilir test etmedim.