title: How to return both null and not-null values in one query
body: <p>I have an integer field person_id with the default value of NULL. I am using a stored procedure and pulling people names and address. if a user does not pass a value all records are pulled both, null and not nulls. How do I do it. May be Case statement or otherwise?</p>
  
  <pre><code>my_procedure(          &lt;--- this is pseudo code
  @person_id int null
  begin
  select name, address from PERSON
  WHERE person_id like case NULL then NULL else '%'
  end
  </code></pre>
  
  <p>Null requires -> IS NULL
  number requires = 123</p>
  
  <p><strong>EDIT</strong>
  I need a condition too, if nothing is passed, all values are pulled. If something is passed, that value is searched</p>