title: How to query the maximum value of two columns in two different tables?
body: <p>I have a requirement.</p>
  
  <p>I have two tables say TableA and TableB. Both having a column called "rec_id". My requirement is to get the maximum of the values contained in these two columns using a single query.</p>
  
  <p>eg: In TableA, I have "rec_id" values as {1,5,6} and in TableB, I have "rec_id" values as {1,4,2}. So after executing the query, I want "6" as the result since 6 is the maximum value from these two columns, out of these two tables.</p>
  
  <p>Thanks in Advance,
  Anish Kurian</p>