Schema: CREATE TABLE Project_Staff (project_id VARCHAR); CREATE TABLE Projects (project_id VARCHAR)
Question: How many staff does each project has? List the project id and the number in an ascending order.
SQL: SELECT T1.project_id, COUNT(*) FROM Project_Staff AS T1 JOIN Projects AS T2 ON T1.project_id = T2.project_id GROUP BY T1.project_id ORDER BY COUNT(*)