學生成績表sc
學生表student
課程表
use exercise0107;-- 資料庫的名稱
-- 第一步查詢語文，數學的課程號
select cid from course where cname="語文";
select cid from course where cname="數學";
-- 第二步分別查詢每個人的語文成績與數學成績 並給予名稱 tempchinese tempmath
select * from sc where (select cid from course where cname="語文") ;
select * from sc where (select cid from course where cname="數學") ;
-- 第三步聯合學生表查出數學成績小於語文成績的學生姓名
select student.sname from student,
(select * from sc where (select cid from course where cname="語文") ) as tempchinese,
(select * from sc where (select cid from course where cname="數學") ) as tempmath
where tempchinese.sid=student.sid and
tempchinese.sid=tempmath.sid and
tempchinese.score>tempmath.score;
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