How many lessons taught by staff whose first name has letter 'a' in it?
SELECT count(*) FROM Lessons AS T1 JOIN Staff AS T2 ON T1.staff_id = T2.staff_id WHERE T2.first_name LIKE "%a%"
SELECT count(*) FROM Lessons AS T1 JOIN Staff AS T2 ON T1.staff_id = T2.staff_id WHERE T2.first_name LIKE "%a%"
[{'count(*)': 5}]