php面试准备工作

php面试知识点总结

 

 

mysql面试点总结

SQL语句的考察

1.查询001课程比002课程成绩高的所有学生的学号： 

select a.sid,a.score as score1,b.score as score2 from 
(select sid,score from scores where cid = 1)as a 
left join 
(select sid,score from scores where cid = 2) as b 
on b.sid=a.sid where a.score>b.score

2、查询平均成绩大于60分的同学的学号和平均成绩：

select sid,avg(score)as avg_score from scores group by sid having avg_score>60

3、查询所有同学的学号，姓名，选课数，总成绩：

select sid,count(*),sum(score) from scores group by sid

4、查询姓李的老师个数

select count(*) from teacher where tname like '李%'

5、查询没有学过张三老师课的同学学号，姓名：

select a.sid,a.sname,b.score from (select sid,sname from student)as a left join (SELECT sid,score 
FROM scores where cid = (select cid from (select tid from teacher where tname='张三')as c
left join (select cid,tid from course)as d on c.tid=d.tid) group by sid)as b on b.sid=a.sid 
where IFNULL(b.score,'null')=0

6、查询学过001和002课程的同学的姓名学号：

select a.sid,b.score as score1,c.score as score2,a.sname from (
(select sid,sname from student)as a
	left join 
(select sid,score from scores where cid=1)as b
	on b.sid=a.sid left join 
(select sid,score from scores where cid =2)as c
	on c.sid = a.sid) where b.score>0 and c.score>0

7、查询学过叶萍老师课的同学的学号，姓名：

select d.sid,d.sname from(
    (select distinct(sid) from scores where cid = (select b.cid from
        (select tid from teacher where tname = '张三')as a 
	        left join 
        (select tid,cid from course)as b on b.tid=a.tid)
    )as c 
        left join
    (select sid,sname from student)as d
	    on d.sid=c.sid)

8、查询002成绩比001低的同学的学号，姓名：

select d.sid,c.score1,c.score2,d.sname from 
(select a.sid,a.score as score1,b.score as score2 from 
    (select sid,score from scores where cid=1) as a 
        left join 
    (select sid,score from scores where cid =2)as b on b.sid = a.sid where a.score>b.score
)as c 
    left join
(select sid,sname from student)as d 
	on d.sid = c.sid

9、查询所有课程成绩小于60分的同学的学号

select c.sid,c.sname from (select sid,count(*)as tmp1 from scores group by sid)as a left join 
(select sid,count(*)as tmp2 from scores where score<60 group by sid) as b on b.sid=a.sid left join
(select sid,sname from student) as c on c.sid = a.sid  where a.tmp1=b.tmp2

10、查询没有学全 所有课的同学的学号和姓名

select b.sid,b.sname from (select sid,count(*) as course from scores group by sid having 
course<(select count(*) from course) )as a left join (select sid,sname from student) as b 
on b.sid = a.sid

11、查询至少有一门课程与学号1001的同学所学相同的同学的学号和姓名

select a.sid,b.sname from (select distinct(sid) from scores 
where cid in ((select group_concat(cid) from scores where sid = 1)) and sid !=1)as a 
left join (select sid,sname from student)as b on b.sid = a.sid;

 

 

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