title: Stored procedure raising "incompatible with sql_mode=only_full_group_by" despite sql_mode being blank
body: <p>I have a stored procedure that ran fine on MySQL 5.6. During a recent server migration we upgraded to MySQL 5.7.19.</p>
  
  <p>My stored procedure now throws the error:</p>
  
  <p><code>Expression #1 of SELECT list is not in GROUP BY clause and contains nonaggregated column 'utility-monitor.daily_readings.building_id' which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by: CALL monthly_readings(2017, 1, NULL, 1, 1))</code></p>
  
  <p>I've set the <code>sql_mode</code> to <code>""</code> via the <code>/var/mysql/my.cnf</code> file, restarted the mysql service and logged in via console to confirm that <code>sql_mode</code> is blank via <code>SELECT @@sql_mode;</code></p>
  
  <p>Despite all that, I continue to receive the above error when I try to run my stored procedure.</p>
  
  <p>What can I do next to continue troubleshooting where this error is coming from?</p>