看似简单,但其实包含很多技巧思维
1.查询课程表中所有科目大于80的学生
select distinct name from student where name not in (select name from student where grade<80);
这样是错误的
select distinct name from student where name in (select name from student where grade>=80);这样代表只要有一门大于80即可
看似简单,但其实包含很多技巧思维
1.查询课程表中所有科目大于80的学生
select distinct name from student where name not in (select name from student where grade<80);
这样是错误的
select distinct name from student where name in (select name from student where grade>=80);这样代表只要有一门大于80即可
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