A Database Error Occurred

Error Number: 1055

Expression #2 of SELECT list is not in GROUP BY clause and contains nonaggregated column 'abhaf_bilingual.newsletter.month' which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by

SELECT newsletter.newsletter_id,newsletter.month,newsletter.year,newsletter.type, added_on_date,newsletter.status,file_name, newsletter_category.perma_link FROM newsletter LEFT JOIN newsletter_category ON newsletter_category.news_categ_id=newsletter.news_categ_id LEFT JOIN file_gallery ON file_gallery.type_id=newsletter.newsletter_id AND file_gallery.type=0 AND file_gallery.image_type=1 WHERE newsletter.status=1 and newsletter.language_id = 1 AND newsletter.type=1 and newsletter.news_categ_id=1 group by newsletter.newsletter_id ORDER BY newsletter.month DESC

Filename: models/Newsletter_model.php

Line Number: 12