title: MySQL delete from table where column is empty
body: <p>I am trying to delete inserted data from table1 where a certain column from table2 (sname) is null. I am trying to achieve this through a left outer join but don't understand yet the fundamentals of it.</p>
  
  <pre><code> table1 | anum  pnum 
           ===========
            001   001
            002   001
            003   002
            004   002
  
  
   table2 | anum  sname
           ============
            001   'cooking'
            001   'cleaning'
            002   'teaching'
            003   NULL
  </code></pre>
  
  <p>Any tips are highly appreciated.    </p>