title: INSERT INTO and DELETE... IF/WHERE a column in different table
body: <p>What statement can I use to INSERT INTO tableA a new row ONLY IF a specific column in tableB equals some value, where tableB contains "itemid" and tableA includes "itemid" as well. I thought of INNER JOIN but is that possible somehow?</p>
  
  <p>I also need exactly the same approach for DELETE.</p>