title: No result when sending a mySql query in python3.7 with a group by
body: <p>I am facing an issue querying my mysql table in python3.7 (mysql-connector==2.2.9).
  Here is my code: </p>
  
  <pre><code>import mysql.connector 
  
  conn = mysql.connector.connect(
      host="127.0.0.1", 
      user="jeremy", 
      password="password", 
      database="facebook_messenger"
  )
  
  cursor = conn.cursor()
  
  query = "SELECT title, uuid, sender, MIN(sent_at), MAX(sent_at) FROM messages GROUP BY title, uuid, sender;"
  #query = "SELECT title, uuid, sender FROM messages;"
  cursor.execute(query)
  results = cursor.fetchall()
  print(results)
  </code></pre>
  
  <p>I don't have any error but the results is [].</p>
  
  <p>This is weird because if I run the same query right in my mysql it works. </p>
  
  <p>Also, if I run a simple select (as commented in my code) I get the results.</p>
  
  <p>My hypothesis then, it is that the group by does not work.</p>
  
  <p>Any idea ? </p>