title: What does SQL clause "GROUP BY 1" mean?
body: <p>Someone sent me a SQL query where the <code>GROUP BY</code> clause consisted of the statement: <code>GROUP BY 1</code>.</p>
  
  <p>This must be a typo right? No column is given the alias 1. What could this mean? Am I right to assume that this must be a typo?</p>