求一条mysql5.0的触发器语句

语句主要实现在“Product”表中插入一条记录时，将主键“Product_id”变成“CP001”、“CP002”.....的形式

create trigger update_product_primary_key before insert on Product for each row begin select count(*) into @count from Product; set new.Product_id =concat('CP',lpad(@count + 1,3,'0')); end;

create trigger update_product_primary_key before insert on Product for each row begin select count(*) into @count from Product; set new.Product_id = concat('CP000',@count + 1); end;