華南農(nóng)業(yè)大學(xué)數(shù)據(jù)庫(kù)系統(tǒng)概念實(shí)驗(yàn)報(bào)告三(留存版)
【正文】 dentgroup by namehaving count(grade)=2。)(5) Display the IDs of all instructors who have never taught a course (Notesad1) Oracle uses the keyword minus in place of except。 AND credits = 3(2) For the student with ID 12345 (or any other value), show all course_id and title of all courses registered for by the student. SELECT course_id,titleFROM takes NATURAL JOIN courseWHERE id = 123454. As above, but show the total number of credits for such courses (taken by that student). Don39。t forget the distinct clause!) select distinct ID,name from teaches natural join instructor where not exists ((select course_id from course)except (select course_id from course where course_id like 39。))。(3) As above, but display the total credits for each of the students, along with the ID of the student。t bother about students who have not regist
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