MySQL to 5.7 : SELECT not in GROUP BY clause

[ryanhowdy]

Assigned to Problems, Issues and Bugs #30806. As reported in Tender:

Hi there, I have upgraded MySQL to 5.7 ,now my hosted fcms website is giving me this error:

" Array ( [0] => 42000 [1] => 1055 [2] => Expression #1 of SELECT list is not in GROUP BY clause and contains nonaggregated column 'kdymffnf_fcms303.p.category' which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by )"

Please assist how to fix this. It works well on MySQL 5.6 but getting error on 5.7. Can anyone kindly assist.