แสดงชื่อผู้บริจาคเงินบริจาคให้ทั้งโรงเรียน "เกลนน์" และ "ไทรทัน" ไม่จำเป็นต้องใช้โต๊ะทั้งหมด
Show the names of donors who donated to both school "Glenn" and "Triton."It is not neccessary to use all the tables.
 school:  (school_id [ VARCHAR ] school_name [ VARCHAR) ]
SELECT T1.donator_name FROM endowment AS T1 JOIN school AS T2 ON T1.school_id = T2.school_id WHERE T2.school_name = 'Glenn' INTERSECT SELECT T1.donator_name FROM endowment AS T1 JOIN school AS T2 ON T1.school_id = T2.school_id WHERE T2.school_name = 'Triton'