2
Interresting,
I 've tryed but my MYSQL courses are too far in my head...
I understand what we should do it but not in SQL !
1 - find all uid with with groupid = 5 (easy : SELECT * FROM `xe07_groups_users_link` WHERE `groupid` = 5)
2 - List for each uid with groupid=5, and find their other groupid <> 5
3 - delete these lines
So you keep all uid with groupid = 5
I want to see the SQL request
"remove duplicate occurrence in SQL" but dont keep the first occurrence (keep the occurence with groupid = 5 )