select * from t_pub_dic dic,t_pub_obj_base bas where dic.f_obj_pid=bas.f_pid and dic.f_dic_name ='BZ37';
select * from (select * from t_pub_dic dic where dic.f_dic_name='BZ37') dic,t_pub_obj_base bas where dic.f_obj_pid=bas.f_pid
请问上面两个语句在执行效率上有什么差别?