How to prevent duplicate Usernames in php/mysql
45300
How to prevent duplicate usernames when people register?
24316
Usernames vs. Real Names
145332
Does MySQL overwrite a column of same value on update?
101638
How do I make sure that values from MySQL keep their type in PHP?
108153
Preparing a MySQL INSERT/UPDATE statement with DEFAULT values
85575
How to prevent user registration
12087
How to drop unique in MySQL?
75643
How to handle people impersonating other people by choosing the same display name
74188
How can I avoid SQL injection attacks in my ASP.NET application?
21275
same user two login - chat username on site x shows SO user name
3705
How can I prevent SQL injection with dynamic tablenames?
55676
SQL distinct for 2 fields in a database
80577
How to delete duplicates on a MySQL table?
123625
Prevent Multiple Form Submissions (Server side)
39806
Correct MySQL username/password, but getting Access Denied error when run from script
86181
Update table values from another table with the same user name
51375
Why would one limit username format?