Show the name and theme for all concerts and the number of singers in each concert.
SELECT T2.concert_name ,  T2.theme ,  count(*) FROM singer_in_concert AS T1 JOIN concert AS T2 ON T1.concert_id  =  T2.concert_id GROUP BY T2.concert_id
SELECT T2.concert_name ,  T2.theme ,  count(*) FROM singer_in_concert AS T1 JOIN concert AS T2 ON T1.concert_id  =  T2.concert_id GROUP BY T2.concert_id
[{'concert_Name': 'Auditions', 'Theme': 'Free choice', 'count(*)': 3}, {'concert_Name': 'Super bootcamp', 'Theme': 'Free choice 2', 'count(*)': 2}, {'concert_Name': 'Home Visits', 'Theme': 'Bleeding Love', 'count(*)': 1}, {'concert_Name': 'Week 1', 'Theme': 'Wide Awake', 'count(*)': 1}, {'concert_Name': 'Week 1', 'Theme': 'Happy Tonight', 'count(*)': 2}, {'concert_Name': 'Week 2', 'Theme': 'Party All Night', 'count(*)': 1}]