Update Text Field

[VBDev]

Hurm, how to update a field of text to add sthg at then end ?
With a INT field, no problem, an update query with field = field + X works perfectly but I want to do this :

$DB_site->query("UPDATE ". TABLE_PREFIX ."password SET users=users & '$bbuserinfo[userid]' WHERE postid='$postid'");

This doesn't work
I've tried with + instead of the &, same result, it doesn't work correctly

By searchin on mysql.com (thanks Dean :lick: ), I found this function concat_ws but I don't know the exact structure and it doesn't work fine with this :

$DB_site->query("UPDATE ". TABLE_PREFIX ."password SET users=concat_ws(users,'$bbuserinfo[userid],') WHERE postid='$postid'");

It only replace my field with the new userid

How can I do this with only one query ?!

Thanks by advance