面试常考的 group by +having 试题
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net更改
one
suggest
sql
学生
id
name
create table sd (id int primary key ,name varchar(22));
insert into sd values(1,'a');
insert into sd values(2,'b');
insert into sd values(3,'c');
课程
id
name
sid
chengji
create table course (id int primary key ,name varchar(22),sid int,chengji int);
insert into course values(1,'ca',1,99);
insert into course values(2,'cb',1,98);
insert into course values(3,'cc',1,22);
insert into course values(4,'cb',2,18);
insert into course values(5,'cc',2,82);
1 选了2们以上的学号
select s.id from sd s,course c where c.sid = s.id group by s.id having count(*) >=2 order by c.sid desc;
select s.id from sd s left join course c on c.sid = s.id group by s.id having count(*) >=2 order by c.sid desc;
2 总成绩大于150的学号
select s.id from sd s,course c where c.sid=s.id group by s.id having sum(c.chengji) >50;
one
suggest
sql
学生
id
name
create table sd (id int primary key ,name varchar(22));
insert into sd values(1,'a');
insert into sd values(2,'b');
insert into sd values(3,'c');
课程
id
name
sid
chengji
create table course (id int primary key ,name varchar(22),sid int,chengji int);
insert into course values(1,'ca',1,99);
insert into course values(2,'cb',1,98);
insert into course values(3,'cc',1,22);
insert into course values(4,'cb',2,18);
insert into course values(5,'cc',2,82);
1 选了2们以上的学号
select s.id from sd s,course c where c.sid = s.id group by s.id having count(*) >=2 order by c.sid desc;
select s.id from sd s left join course c on c.sid = s.id group by s.id having count(*) >=2 order by c.sid desc;
2 总成绩大于150的学号
select s.id from sd s,course c where c.sid=s.id group by s.id having sum(c.chengji) >50;
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