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

^([a-zA-Z0-9]*)([a-zA-Z]+)([a-zA-Z0-9]*)$