title: delete records from foreign-key constraint in table2 which does have primary key in table1
body: <p>Suppose Table1 has</p>
  
  <pre><code>wordid col2
   1     x
   2     y
   3     x
  </code></pre>
  
  <p>Now table2 has</p>
  
  <pre><code>wordid col3
    1    a
    2    b
    3    c
    4    d
  </code></pre>
  
  <p>The "wordid" column in the "table1" table is the PRIMARY KEY in the "table1" table.</p>
  
  <p>The "wordid" column in the "table2" table is a FOREIGN KEY in the "table2" table.</p>
  
  <p>I want to delete all records in "table2" that are not bound to any constraint. ( here row with wordid "4" needs to be deleted)</p>