I am looking for a mysql query which will return me all the rows,
where a particular field is made up of characters from a given string.

e.g. I 've this string: $input = 'abcdef';
now, I am looking for mysql to result all those rows, where e.g. 'name' consists of letters from $input.

Ben açıkça kendimi ifade umut .. :)

EDIT: Also, for the query you suggest, will it really improve performance, if we are just searching for strings made of letters a-z instead of some patterns, esp. when we are requesting data every 2 seconds.
The thing is that for now, my requirements are to only search among numeric, alpha or alphanumeric formats.. I will be using the exclusive patterns later on.

Regards
Nikhil Gupta