title: SQL return a row when filter doesn't exist
body: <p>Say I have a table that contains a column with a number in it, when I match that number in a where statement I want the value from some other column in that row if that some other column is empty. Easy enough</p>
  
  <p>I also want listed however, when that number just plain doesn't exsist. IS NULL doesn't work since it's just plain not there</p>
  
  <pre><code>(row)   id | num | text
   1      1  | 5433 | a
   2      1  | 1234 | b
   3      3  | 4532 | b
   4      3  | 1234 | c
   5      4  | 5312 | d
   6      4  | 1234 | 
   7      5  | 4654 | a
  </code></pre>
  
  <p>query...</p>
  
  <pre><code>select text
  from table
  where text IS NULL AND num=1234
  </code></pre>
  
  <p>Would return row 6, however I want it to also return id 5 since it doesn't not contain a 1234 value, like so</p>
  
  <pre><code>5 | 1234 |
  </code></pre>