title: Generate sequence # in Hive Select Query
body: <p>How can i generate a select query in a way that i can select 5 columns and assign a unique row # for each of those rows. 
  e.g. I have a table A as 
  Col1, Col2, Col3, Col4 </p>
  
  <p>Desired OUTPUT from Query: 
  row_id, Col1, Col2, col3, col4 </p>
  
  <p>where row_id ranges from 1 till total # of rows. </p>