MySQL server has gone awaySELECT exercises.*, ueb.bookmarked, video_link_w,  coalesce(caption_en, caption) caption, coalesce(title_en, title) title, coalesce(content_en, content) content, coalesce(teaser_en, teaser) teaser, coalesce(shorttext_1_en, shorttext_1) shorttext_1, coalesce(shorttext_2_en, shorttext_2) shorttext_2, coalesce(smallpicture_en, smallpicture) smallpicture, coalesce(video_link_en, video_link) video_link, coalesce(video_link_1_en, video_link_1) video_link_1, coalesce(exercises.url_en, CONCAT('/en/exercises/', exercises.id) ) as url  FROM exercises
				LEFT OUTER JOIN user_exercise_bookmarks ueb ON ueb.user_id = 1710 AND exercises.id = ueb.exercise_id 
		 		WHERE exercises.id=951