mysql (_mysql_exceptions.OperationalError) (1055, "Expression #1 of SELECT list is not in GROUP BY clause

sudo gedit /etc/mysql/my.cnf
在打开的my.cnf文件中添加

sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES

保存，退出

重启mysql：/etc/init.d/mysql restart

登录mysql：mysql -u root -p
mysql ->select @@sql_mode;

验证sql_mode的值是否改变.