title: BigQuery add number to row_number()
body: <p>I'm new to BigQuery and I would like to ask if there is a possible way to set a starting number for row_number() function using the Legacy SQL. I have tried this code:</p>
  
  <pre><code>SELECT
  ROW_NUMBER() OVER(order by col1) + 20 AS xxx
  From tb1
  </code></pre>
  
  <p>but it return this error:</p>
  
  <blockquote>
    <p>Error: Encountered " "+" "+ "" at line 2, column 44. Was expecting: </p>
  </blockquote>
  
  <p>Any answer will be greatly appreciated</p>
  
  <p>Thanks!</p>