SQLSTATE[42000]: Syntax error or access violation: 1055 Expression #3 of SELECT list is not in GROUP BY clause and contains nonaggregated

Run:

sudo mysql -u root -p
mysql> SELECT @@global.sql_mode;

(Then optionally copy the output to your notes somewhere in case you want to revert to those original settings later.)

And change the SQL Mode for your MySQL Server Instance:

mysql> SET GLOBAL sql_mode=(SELECT REPLACE(@@sql_mode,'ONLY_FULL_GROUP_BY',''));

(If you ever want to roll back, you could run something like mysql> SET GLOBAL sql_mode="ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_ENGINE_SUBSTITUTION"; using the value you saved.)

A more permanent way (which will survive restarts of MySQL) would be using the MySQL configs. Go to /etc/mysql/my.cnf (or you may need to run sudo vim /etc/mysql/mysql.conf.d/mysql.cnf):

• Add a section for
  [mysqld] and right below it add the statement
  sql_mode = "" or something like sql_mode="STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_ENGINE_SUBSTITUTION".

• Restart the MySQL service:

   sudo systemctl restart mysql
  

(or sudo service mysql restart)

See also https://dba.stackexchange.com/a/113153/18098