http://chenxy.blog.51cto.com/729966/728112,
参考文档二：http://topic.csdn.net/u/20080508/10/4b56808e-ab77-4d6e-8e75-47f281e8e33c.html
例如下面的sql语句：
单个字段去掉重复：
select pp.p_product_id, pp.product_name, pp.product_level_name, ud.depart_path_name, pp.recommand_level, pp.product_type, pp.travelline_type, pp.departure, pp.destination, pp.sale_city_codes, pp.travel_day_span, pp.valid, pp.modify_datetime from p_product pp ,u_department ud where pp.u_department_id=ud.department_id and pp.u_department_id in(select us.u_department_id from p_product us group by us.u_department_id having count(*)>1) order by pp.modify_datetime desc;
多个字段去掉重复：
select pp.p_product_id, pp.product_name, pp.product_level_name, ud.depart_path_name, pp.recommand_level, pp.product_type, pp.travelline_type, pp.departure, pp.destination, pp.sale_city_codes, pp.travel_day_span, pp.valid, pp.modify_datetime from p_product pp ,u_department ud where pp.u_department_id=ud.department_id and (pp.u_department_id,ud.depart_path_name)in(select us.u_department_id,ud.depart_path_name from p_product us,u_department ud group by us.u_department_id,ud.depart_path_name having count(*)>1) order by pp.modify_datetime desc;
最好不使用disctinct
本文转自hcy's workbench博客园博客，原文链接：http://www.cnblogs.com/alterhu/archive/2012/06/20/2556375.html
，如需转载请自行联系原作者。
