regex to check the string contains only letter and numbers but not only numbers

Question

I need a help with regex which checks the string contains only letter and numbers but not only numbers

Valid

* letters
* 1wret
* 0123chars
* chars0123
*          


        

Answer 1

Personally (I hate regex and find them generally to be hard to maintain), I'd do it in two steps.

1. Is it all alphanumeric?
2. Is there at least one letter?