title: How to select only 1 row if duplicate rows (Oracle)
body: <p>I have a table contains order information like below:</p>
  
  <p><img src="https://i.stack.imgur.com/jDLHu.png" alt=""></p>
  
  <p>As we can see from that table, each order_no has several duplicates. So what I want is to keep only one row for each order_no (no matter which )</p>
  
  <p>Does anyone know how to do this?(And I tried 'distinct', but some of the columns of those duplicate rows are different, so 'distinct' can't work in here)</p>