mysql多表多字段查询并去重 - MySQL-ChinaUnix.net
http://bbs.chinaunix.net/forum.php?mod=viewthread&tid=4254936
MySQL多表查询 - 淋哥 - 博客园
https://www.cnblogs.com/xuchunlin/p/6045263.html
mysql-MySQL根据两列进行去重——****问答频道
https://ask.****.net/questions/699913
MySQL根据两列去重-****论坛
https://bbs.****.net/topics/392261242
MySQL根据两列去重_MYSQL_编程问答
http://www.codes51.com/itwd/4462413.html
mysql查询根据部分字段去重 - maoyuanming0806的博客 - ****博客
https://blog.****.net/maoyuanming0806/article/details/77950392
mysql数据库，在查询列名里子查询一列由两列组合去重的个数如何实现？-****问答
https://ask.****.net/questions/190741
mysql如何去除两个字段数据相同的记录？ - 知乎
https://www.zhihu.com/question/33189744
sql server - How can I remove duplicate rows? - Stack Overflow
https://*.com/questions/18932/how-can-i-remove-duplicate-rows
Mysql数据库如何实现多列组合去重复，然后统计个数？-****问答
https://ask.****.net/questions/190990
MySQL exists的用法介绍 - ﹏Sakura - 博客园
http://www.cnblogs.com/glory-jzx/archive/2012/07/19/2599215.html