Checking duplicate user in a DATABASE?

[bilis_money]

hi,

i would like to check a user duplicaet inside a MySQL database.
So what would be the right query for this in MySQL or PHP?
can you show me example snippet codes?


thanks in advance

[silentwf]

Hello bilis
Anyways, I ran into this problem myself, but now I can provide you with the answer  :D
[code]
$query  = "SELECT username FROM users WHERE username='$username'";
$result = mysql_query($query);
$checkUsername = mysql_fetch_array($result);

if!isset($checkUsername['username']){ //if the username is not taken
//do something
} else {
//report error
}
[/code]
Hope this helps

[ignace]

I normally set this into the database that the username has to be an unique value
Also silentwf I do not recomment using:

[code]
<?php
if !isset($checkUsername[...
// Instead use
if (!in_array($username, $checkUsername)) { ...
?>
[/code]

[silentwf]

How come?

[bilis_money]

ok, thanks i'll try it.

[ronverdonk]

Forgive me, but why don't you just do a

[code]$query  =  "SELECT COUNT(*) FROM users WHERE username='$username'";[/code]

and if the result > 1 you know you have duplicate(s).

[xec]

"[font=Verdana][u][b]i would like to check a user duplicate inside a MySQL database.[/b][/u][/font]"


Guys , what if i want to get count +  user name that have duplcate entry through a sql  query with out providin any $username

[ignace]

xec now your obsetly making it difficult, you need the where clausule otherwise you can not check where something is equal/duplicate

[code]
$query = "SELECT `username`, COUNT(`username`) AS `DuplicateEntries` FROM `users` WHERE `username`='$username'";// will possibly not work... therefore rather use:
$Query = mysql_query("SELECT `username` FROM `users` WHERE `username`='$username'");
$Rows = count(mysql_fetch_array($Query));
[/code]

[ronverdonk]

Try this one:
[code] select count(naam) , naam from xx group by naam;[/code]

[ronverdonk]

Can I guess the next question: how do I remove the rows with the duplicate usernames?

[xec]

ronverdonk , this query doesnt give us the solution...


i still havent got the answers , its possible . then i have to find out this query....  ;)

[ronverdonk]

Last try. If you ONLY want to display the usernames that are duplicate with their occurrence count:
[code]select count(username) as no , username from yourtable group by username having no>1[/code]

[xec]

:D great, this works, listing all the names of writer with the no. of time they have been entred....

select count(writer_name) as no , writer_name from writer_info group by writer_name