title: db2 select distinct rows, but select all columns
body: <p>Experts, I have a single table with multiple columns. col1, col2, col3, col4, col5, col6</p>
  
  <p>I need to <code>select distinct (col4)</code>,  but I need all other columns also on my output.</p>
  
  <p>If I run, this ( <code>select distinct(col4 ) from table1</code> ), then I get only col4 on my output.</p>
  
  <p>May I know, how to do it on db2?.</p>
  
  <p>Thank you</p>