mysql多表多字段查詢並去重 - MySQL-ChinaUnix.net
http://bbs.chinaunix.net/forum.php?mod=viewthread&tid=4254936
MySQL多表查詢 - 淋哥 - 博客園
https://www.cnblogs.com/xuchunlin/p/6045263.html
mysql-MySQL根據兩列進行去重——CSDN問答頻道
https://ask.csdn.net/questions/699913
MySQL根據兩列去重-CSDN論壇
https://bbs.csdn.net/topics/392261242
MySQL根據兩列去重_MYSQL_編程問答
http://www.codes51.com/itwd/4462413.html
mysql查詢根據部分字段去重 - maoyuanming0806的博客 - CSDN博客
https://blog.csdn.net/maoyuanming0806/article/details/77950392
mysql數據庫，在查詢列名里子查詢一列由兩列組合去重的個數如何實現？-CSDN問答
https://ask.csdn.net/questions/190741
mysql如何去除兩個字段數據相同的記錄？ - 知乎
https://www.zhihu.com/question/33189744
sql server - How can I remove duplicate rows? - Stack Overflow
https://stackoverflow.com/questions/18932/how-can-i-remove-duplicate-rows
Mysql數據庫如何實現多列組合去重復，然后統計個數？-CSDN問答
https://ask.csdn.net/questions/190990
MySQL exists的用法介紹 - ﹏Sakura - 博客園
http://www.cnblogs.com/glory-jzx/archive/2012/07/19/2599215.html