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Question

在珍妮弗·威登的dbclass創建SQL，她給獲得一個大學的例子配對與他們申請的最高GPA。該SQL低於

select college.cname, state, gpa  
    from college, apply, student 
where college.cname = apply.cname 
    and apply.sid = student.sid 
    and gpa >= all (select gpa 
        from student,apply 
        where student.sid = apply.sid 
    and apply.cname = college.cname); 

我想知道如何創建查詢發現與申請人

我知道這是可以做到如下

select college.cname, state, gpa  
    from college, apply, student 
where college.cname = apply.cname 
    and apply.sid = student.sid 
    and gpa = (select min(gpa) from student); 

但如何的最低 GPA配對學院我這樣做，沒有使用最小？

Answer 1

select college.cname,state,gpa  
from college c 
    join apply a On a.cname = c.cname 
    join student s On s.sid = apply.sid 
where Not exists(select * from student 
       Where gpa < s.gpa);