title: SQL wildcards: Dictating amount of characters and values for each character
body: <p>I want to look for a very specific substring which is between 3 and 5 characters. Each character can be numeric [0-9] or [a-z].</p>
  
  <p>The substring I'm looking for is either a word or number. I know how to dictate the exact amount of chars with "_" and using "[]" to tell sql what characters
  I'm looking for but how do I mix them?</p>
  
  <p>I've tried all kind of nonsense but nothing worked.</p>