text: /*number of groups*/
  SELECT COUNT(*) FROM ~groups~
  
  /*have description*/
  SELECT COUNT(*) FROM ~groups~ WHERE description IS NOT NULL
  
  /*avg. length of description*/
  SELECT AVG(LENGTH(description)) FROM ~groups~
  
  /*median length of description*/
  SELECT MEDIAN(LENGTH(description)) FROM ~groups~
  
  /*maximum length of description*/
  SELECT MAX(LENGTH(description)) FROM ~groups~
  
  /*open*/
  SELECT COUNT(*) FROM ~groups~ WHERE join_mode = 'open'
  
  /*membership dues*/
  SELECT COUNT(*) FROM ~groups~ WHERE membership_dues_fee IS NOT NULL
  
  /*number of different organizers*/
  SELECT COUNT(DISTINCT(organizer_member_id)) FROM ~groups~
  
  /*average rating*/
  SELECT AVG(rating) FROM ~groups~
  
  /*average rating (!= 0)*/
  SELECT AVG(rating) FROM ~groups~ WHERE rating != 0
  
  /*median rating*/
  SELECT MEDIAN(rating) FROM ~groups~
  
  /*sponsored groups*/
  SELECT COUNT(*) FROM ~groupsponsors~
  
  /*number of categories*/
  SELECT COUNT(DISTINCT category_id) FROM ~groups~
  
  /*most prominent category*/
  SELECT name FROM ~categories~ GROUP BY name, id ORDER BY COUNT(id) DESC LIMIT 1
  
  /*Groups that have at least one event*/
  SELECT COUNT(group_id)
  FROM (
    SELECT groups.id AS group_id, COUNT(events.id) AS n_events
    FROM ~groups~ groups
    JOIN ~events~ events
    ON groups.id = events.group_id
    GROUP BY groups.id
  )
  
  /*Events per group with events*/
  SELECT AVG(n_events)
  FROM (
    SELECT groups.id, COUNT(events.id) AS n_events
    FROM ~groups~ groups
    JOIN ~events~ events
    ON groups.id = events.group_id
    GROUP BY groups.id
  )
  