A Database Error Occurred

Error Number: 1055

Expression #2 of SELECT list is not in GROUP BY clause and contains nonaggregated column 'book_open101.obo5_posts.date_posted' which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by

SELECT COUNT(obo5_posts.id) AS posts_count, obo5_posts.date_posted FROM obo5_posts WHERE obo5_posts.status = 'published' GROUP BY SUBSTRING(obo5_posts.date_posted, 1, 7) ORDER BY `obo5_posts`.`date_posted` DESC LIMIT 10

Filename: models/Blog_m.php

Line Number: 132