มีผู้บริจาคเงินบริจาคให้กับโรงเรียนชื่อ "เกลน" กี่คน?ไม่จำเป็นต้องใช้โต๊ะทั้งหมด
How many donors have endowment for school named "Glenn"?It is not neccessary to use all the tables.
 school:  (school_id [ VARCHAR ] school_name [ VARCHAR) ]
SELECT COUNT(DISTINCT T1.donator_name) FROM endowment AS T1 JOIN school AS T2 ON T1.school_id = T2.school_id WHERE T2.school_name = "Glenn"