php - Get the returned value from a prepared statement MySQL -

i trying make stored procedure want random value on database table name , other conditions of query dynamic (in stored proc params).

    drop procedure if exists `myproc`;  delimiter // create procedure `myproc`(in `tablename` varchar(50), in `isshow` tinyint(1), in `isadd` tinyint(1)) begin     set @tname := tablename;     set @isshow := isshow;     set @isadd := isadd;     set @pcode := '';      set @s = concat('select t.pcode         ', @tname, ' t          join (select round(rand() * (select max(idx) ', @tname,' )) id) x                       t.idx >= x.id ,              t.isshow = ', @isshow,' ,             t.isadd = ', @isadd,         ' limit 1');      checkhand: while (!@pcode)         prepare sp_query @s;          execute sp_query;          deallocate prepare sp_query;          leave checkhand;     end while ; end // delimiter ; 

since use @var tablename, referred so , create sql query in concat run stored procedure. right now, tables has holes did while loop until record pcode value.

my problem was, still returning blank pcode means @pcode var doesnt return value of query. don't have idea how store result of query ran in prepared statement variable , return result of stored procedure.

any do. please correct me. not pro sql user. thanks

my while loop supposed this:

while (!t.pcode) {     // query , check if t.pcode     return t.pcode }