องค์กรประเภทใดที่มีบุคลากรวิจัยมากที่สุด?ไม่จำเป็นต้องใช้ตารางทั้งหมด
What is the type of the organization with the most research staff?It is not neccessary to use all the tables.
 project_staff:  staff_id [ number]  project_id [ number]  role_code [ text]  date_from [ time]  date_to [ time]  other_details [ text] 
SELECT T1.organisation_type FROM organisations AS T1 JOIN research_staff AS T2 ON T1.organisation_id = T2.employer_organisation_id GROUP BY T1.organisation_type ORDER BY COUNT(*) DESC LIMIT 1