符合中小企业对网站设计、功能常规化式的企业展示型网站建设
本套餐主要针对企业品牌型网站、中高端设计、前端互动体验...
商城网站建设因基本功能的需求不同费用上面也有很大的差别...
手机微信网站开发、微信官网、微信商城网站...
select * from course;
+--------------+----------------+--------------+--+
| course.c_id | course.c_name | course.t_id |
+--------------+----------------+--------------+--+
| 01 | 语文 | 02 |
| 02 | 数学 | 01 |
| 03 | 英语 | 03 |
+--------------+----------------+--------------+--+
专注于为中小企业提供成都网站制作、网站建设服务,电脑端+手机端+微信端的三站合一,更高效的管理,为中小企业仁布免费做网站提供优质的服务。我们立足成都,凝聚了一批互联网行业人才,有力地推动了上千余家企业的稳健成长,帮助中小企业通过网站建设实现规模扩充和转变。
select * from score;
+-------------+-------------+----------------+--+
| score.s_id | score.c_id | score.s_score |
+-------------+-------------+----------------+--+
| 01 | 01 | 80 |
| 01 | 02 | 90 |
| 01 | 03 | 99 |
| 02 | 01 | 70 |
| 02 | 02 | 60 |
| 02 | 03 | 80 |
| 03 | 01 | 80 |
| 03 | 02 | 80 |
| 03 | 03 | 80 |
| 04 | 01 | 50 |
| 04 | 02 | 30 |
| 04 | 03 | 20 |
| 05 | 01 | 76 |
| 05 | 02 | 87 |
| 06 | 01 | 31 |
| 06 | 03 | 34 |
| 07 | 02 | 89 |
| 07 | 03 | 98 |
+-------------+-------------+----------------+--+
select * from student;
+---------------+-----------------+------------------+----------------+--+
| student.s_id | student.s_name | student.s_birth | student.s_sex |
+---------------+-----------------+------------------+----------------+--+
| 01 | 赵雷 | 1990-01-01 | 男 |
| 02 | 钱电 | 1990-12-21 | 男 |
| 03 | 孙风 | 1990-05-20 | 男 |
| 04 | 李云 | 1990-08-06 | 男 |
| 05 | 周梅 | 1991-12-01 | 女 |
| 06 | 吴兰 | 1992-03-01 | 女 |
| 07 | 郑竹 | 1989-07-01 | 女 |
| 08 | 王菊 | 1990-01-20 | 女 |
+---------------+-----------------+------------------+----------------+--+
select * from teacher;
+---------------+-----------------+--+
| teacher.t_id | teacher.t_name |
+---------------+-----------------+--+
| 01 | 张三 |
| 02 | 李四 |
| 03 | 王五 |
+---------------+-----------------+--+
with one as
(select * from score where c_id = 01),
two as
(select * from score where c_id = 02),
result as (select o.s_id, o.s_score 01_score,t.s_score 02_score from one o join two t on o.s_id = t.s_id where o.s_score > t.s_score )
select s.*,01_score,02_score from result r join student s on s.s_id = r.s_id;
+---------+-----------+-------------+----------+-----------+-----------+--+
| s.s_id | s.s_name | s.s_birth | s.s_sex | 01_score | 02_score |
+---------+-----------+-------------+----------+-----------+-----------+--+
| 02 | 钱电 | 1990-12-21 | 男 | 70 | 60 |
| 04 | 李云 | 1990-08-06 | 男 | 50 | 30 |
+---------+-----------+-------------+----------+-----------+-----------+--+
with one as
(select * from score where c_id = 01),
two as
(select * from score where c_id = 02),
result as (select o.s_id, o.s_score 01_score,t.s_score 02_score from one o join two t on o.s_id = t.s_id where o.s_score < t.s_score )
select s.*,01_score,02_score from result r join student s on s.s_id = r.s_id;
+---------+-----------+-------------+----------+-----------+-----------+--+
| s.s_id | s.s_name | s.s_birth | s.s_sex | 01_score | 02_score |
+---------+-----------+-------------+----------+-----------+-----------+--+
| 01 | 赵雷 | 1990-01-01 | 男 | 80 | 90 |
| 05 | 周梅 | 1991-12-01 | 女 | 76 | 87 |
+---------+-----------+-------------+----------+-----------+-----------+--+
with avg_student as
(select s_id , avg(s_score) avg_score from score group by s_id having avg_score >= 60)
select s.s_id id, s.s_name name, round(avg_score ,1) avg_score from avg_student a join student s on s.s_id = a.s_id;
+-----+-------+------------+--+
| id | name | avg_score |
+-----+-------+------------+--+
| 01 | 赵雷 | 89.7 |
| 02 | 钱电 | 70.0 |
| 03 | 孙风 | 80.0 |
| 05 | 周梅 | 81.5 |
| 07 | 郑竹 | 93.5 |
+-----+-------+------------+--+
with avg_student as
(select s_id , avg(s_score) avg_score from score group by s_id ),
result as
(select s.s_id id, s.s_name name, nvl(round(avg_score,1),0) avg_score from student s left join avg_student a on s.s_id = a.s_id)
select * from result where avg_score < 60;
+------------+--------------+-------------------+--+
| result.id | result.name | result.avg_score |
+------------+--------------+-------------------+--+
| 04 | 李云 | 33.3 |
| 06 | 吴兰 | 32.5 |
| 08 | 王菊 | 0.0 |
+------------+--------------+-------------------+--+
with t1 as
(select s_id,count(*) course_sum, sum(s_score) sum_score from score group by s_id)
select s.s_id id, s.s_name name, nvl(course_sum,0) course_sum,nvl(sum_score,0) sum_score from student s left join t1 on t1.s_id = s.s_id;
+-----+-------+-------------+------------+--+
| id | name | course_sum | sum_score |
+-----+-------+-------------+------------+--+
| 01 | 赵雷 | 3 | 269 |
| 02 | 钱电 | 3 | 210 |
| 03 | 孙风 | 3 | 240 |
| 04 | 李云 | 3 | 100 |
| 05 | 周梅 | 2 | 163 |
| 06 | 吴兰 | 2 | 65 |
| 07 | 郑竹 | 2 | 187 |
| 08 | 王菊 | 0 | 0 |
+-----+-------+-------------+------------+--+
select count(1) num from teacher where t_name like "李%";
+------+--+
| num |
+------+--+
| 1 |
+------+--+
with t as
(select st.s_id from score s join course c on s.c_id = c.c_id join teacher t on t.t_id=c.t_id join student st on st.s_id = s.s_id where t_name="张三" group by st.s_id)
select student.* from student join t on t.s_id = student.s_id;
+---------------+-----------------+------------------+----------------+--+
| student.s_id | student.s_name | student.s_birth | student.s_sex |
+---------------+-----------------+------------------+----------------+--+
| 01 | 赵雷 | 1990-01-01 | 男 |
| 02 | 钱电 | 1990-12-21 | 男 |
| 03 | 孙风 | 1990-05-20 | 男 |
| 04 | 李云 | 1990-08-06 | 男 |
| 05 | 周梅 | 1991-12-01 | 女 |
| 07 | 郑竹 | 1989-07-01 | 女 |
+---------------+-----------------+------------------+----------------+--+
with t as
(select s.s_id from score s join course c on s.c_id = c.c_id join teacher t on t.t_id=c.t_id where t_name="张三" group by s.s_id)
select student.* from student left join t on t.s_id = student.s_id where t.s_id is null;
+---------------+-----------------+------------------+----------------+--+
| student.s_id | student.s_name | student.s_birth | student.s_sex |
+---------------+-----------------+------------------+----------------+--+
| 06 | 吴兰 | 1992-03-01 | 女 |
| 08 | 王菊 | 1990-01-20 | 女 |
+---------------+-----------------+------------------+----------------+--+
with one as
(select s_id,c_id from score where c_id = 01),
two as
(select s_id,c_id from score where c_id = 02)
select s.* from student s join one o on s.s_id = o.s_id join two t on t.s_id = o.s_id;
+---------+-----------+-------------+----------+--+
| s.s_id | s.s_name | s.s_birth | s.s_sex |
+---------+-----------+-------------+----------+--+
| 01 | 赵雷 | 1990-01-01 | 男 |
| 02 | 钱电 | 1990-12-21 | 男 |
| 03 | 孙风 | 1990-05-20 | 男 |
| 04 | 李云 | 1990-08-06 | 男 |
| 05 | 周梅 | 1991-12-01 | 女 |
+---------+-----------+-------------+----------+--+
with one as
(select s_id,c_id from score where c_id = 01),
two as
(select s_id,c_id from score where c_id = 02)
select s.* from student s join one o on s.s_id = o.s_id left join two t on t.s_id = o.s_id where t.s_id is null;
+---------+-----------+-------------+----------+--+
| s.s_id | s.s_name | s.s_birth | s.s_sex |
+---------+-----------+-------------+----------+--+
| 06 | 吴兰 | 1992-03-01 | 女 |
+---------+-----------+-------------+----------+--+
with t1 as
(select count(c_id) course_num from course ),
t2 as
(select s_id, count(c_id) cour_num from score group by s_id)
select s.* from student s left join t2 on t2.s_id=s.s_id join t1 where t2.s_id is null or t2.cour_num < t1.course_num;
+---------+-----------+-------------+----------+--+
| s.s_id | s.s_name | s.s_birth | s.s_sex |
+---------+-----------+-------------+----------+--+
| 05 | 周梅 | 1991-12-01 | 女 |
| 06 | 吴兰 | 1992-03-01 | 女 |
| 07 | 郑竹 | 1989-07-01 | 女 |
| 08 | 王菊 | 1990-01-20 | 女 |
+---------+-----------+-------------+----------+--+
with t1 as
(select c_id from score where s_id = 01),
t2 as
(select s_id from t1 join score s on s.c_id = t1.c_id group by s_id)
select student.* from student join t2 on t2.s_id = student.s_id where t2.s_id != 01;
+---------------+-----------------+------------------+----------------+--+
| student.s_id | student.s_name | student.s_birth | student.s_sex |
+---------------+-----------------+------------------+----------------+--+
| 02 | 钱电 | 1990-12-21 | 男 |
| 03 | 孙风 | 1990-05-20 | 男 |
| 04 | 李云 | 1990-08-06 | 男 |
| 05 | 周梅 | 1991-12-01 | 女 |
| 06 | 吴兰 | 1992-03-01 | 女 |
| 07 | 郑竹 | 1989-07-01 | 女 |
+---------------+-----------------+------------------+----------------+--+
with num as
(select count(c_id) cour_num from score where s_id = 01),
one as
(select * from score where s_id = 01 ),
t1 as
(select s.s_id , count(s.c_id) c_num from one o join score s on o.c_id = s.c_id group by s.s_id),
t2 as
(select s_id from t1 join num where cour_num=t1.c_num and s_id != 01)
select student.* from student join t2 on t2.s_id = student.s_id;
+---------------+-----------------+------------------+----------------+--+
| student.s_id | student.s_name | student.s_birth | student.s_sex |
+---------------+-----------------+------------------+----------------+--+
| 02 | 钱电 | 1990-12-21 | 男 |
| 03 | 孙风 | 1990-05-20 | 男 |
| 04 | 李云 | 1990-08-06 | 男 |
+---------------+-----------------+------------------+----------------+--+
with t as
(select s.s_id from score s join course c on s.c_id = c.c_id join teacher t on t.t_id=c.t_id where t_name="张三" group by s.s_id)
select student.* from student left join t on t.s_id = student.s_id where t.s_id is null;
+---------------+-----------------+------------------+----------------+--+
| student.s_id | student.s_name | student.s_birth | student.s_sex |
+---------------+-----------------+------------------+----------------+--+
| 06 | 吴兰 | 1992-03-01 | 女 |
| 08 | 王菊 | 1990-01-20 | 女 |
+---------------+-----------------+------------------+----------------+--+
with t1 as
(select s_id,count(c_id) c_num from score where s_score <60 group by s_id having c_num >=2)
select s.s_id,s.s_name,round(avg(s_score),1) avg_score from student s join t1 on t1.s_id = s.s_id join score sc on t1.s_id = sc.s_id group by s.s_id,s.s_name
+---------+-----------+------------+--+
| s.s_id | s.s_name | avg_score |
+---------+-----------+------------+--+
| 04 | 李云 | 33.3 |
| 06 | 吴兰 | 32.5 |
+---------+-----------+------------+--+
with t1 as
(select * from score where c_id = 01 and s_score <60 order by s_score desc)
select s.* from student s join t1 on s.s_id=t1.s_id ;
+---------+-----------+-------------+----------+--+
| s.s_id | s.s_name | s.s_birth | s.s_sex |
+---------+-----------+-------------+----------+--+
| 04 | 李云 | 1990-08-06 | 男 |
| 06 | 吴兰 | 1992-03-01 | 女 |
+---------+-----------+-------------+----------+--+
select s_id , max(case when c_id=01 then s_score else null end ) chinese,max(case when c_id=02 then s_score else null end ) math,max(case when c_id=03 then s_score else null end ) english , round(avg(s_score),2) avg_score from score group by s_id order by avg_score desc;
+-------+----------+-------+----------+------------+--+
| s_id | chinese | math | english | avg_score |
+-------+----------+-------+----------+------------+--+
| 07 | NULL | 89 | 98 | 93.5 |
| 01 | 80 | 90 | 99 | 89.67 |
| 05 | 76 | 87 | NULL | 81.5 |
| 03 | 80 | 80 | 80 | 80.0 |
| 02 | 70 | 60 | 80 | 70.0 |
| 04 | 50 | 30 | 20 | 33.33 |
| 06 | 31 | NULL | 34 | 32.5 |
+-------+----------+-------+----------+------------+--+
–及格为>=60,中等为:70-80,优良为:80-90,优秀为:>=90
with t1 as
(select c_id course_ID ,max(s_score) max_score,min(s_score) min_score,round(avg(s_score),2) avg_score , count(s_id) num_sid, sum(case when s_score >= 60 then 1 else 0 end) pa***ate, sum(case when s_score >= 70 and s_score <80 then 1 else 0 end) mediumRate ,sum(case when s_score >= 80 and s_score <90 then 1 else 0 end) goodRate , sum(case when s_score >= 90 then 1 else 0 end) excellenceRate from score group by c_id )
select course_ID,c_name course_name,max_score,min_score, avg_score, round(pa***ate/num_sid,3) pa***ate,round(mediumRate/num_sid,3) mediumRate,round(goodRate/num_sid,3) goodRate, round(excellenceRate/num_sid,3) excellenceRate from t1 join course c on c.c_id = t1.course_ID;
+------------+--------------+------------+------------+------------+-----------+-------------+-----------+-----------------+--+
| course_id | course_name | max_score | min_score | avg_score | pa***ate | mediumrate | goodrate | excellencerate |
+------------+--------------+------------+------------+------------+-----------+-------------+-----------+-----------------+--+
| 01 | 语文 | 80 | 31 | 64.5 | 0.667 | 0.333 | 0.333 | 0.0 |
| 02 | 数学 | 90 | 30 | 72.67 | 0.833 | 0.0 | 0.5 | 0.167 |
| 03 | 英语 | 99 | 20 | 68.5 | 0.667 | 0.0 | 0.333 | 0.333 |
+------------+--------------+------------+------------+------------+-----------+-------------+-----------+-----------------+--+
select *,row_number() over(partition by c_id order by s_score desc) ranks from score;
+-------------+-------------+----------------+--------+--+
| score.s_id | score.c_id | score.s_score | ranks |
+-------------+-------------+----------------+--------+--+
| 03 | 01 | 80 | 1 |
| 01 | 01 | 80 | 2 |
| 05 | 01 | 76 | 3 |
| 02 | 01 | 70 | 4 |
| 04 | 01 | 50 | 5 |
| 06 | 01 | 31 | 6 |
| 01 | 02 | 90 | 1 |
| 07 | 02 | 89 | 2 |
| 05 | 02 | 87 | 3 |
| 03 | 02 | 80 | 4 |
| 02 | 02 | 60 | 5 |
| 04 | 02 | 30 | 6 |
| 01 | 03 | 99 | 1 |
| 07 | 03 | 98 | 2 |
| 02 | 03 | 80 | 3 |
| 03 | 03 | 80 | 4 |
| 06 | 03 | 34 | 5 |
| 04 | 03 | 20 | 6 |
+-------------+-------------+----------------+--------+--+
with t1 as
(select s_id,sum(s_score) sum_score from score group by s_id order by sum_score desc )
select s.s_id id,s_name name, sum_score, row_number() over(order by sum_score desc) rank from student s join t1 on s.s_id=t1.s_id;
+-------------+---------+-----------+----------+--+
| score.s_id | s_name | sumscore | ranking |
+-------------+---------+-----------+----------+--+
| 01 | 赵雷 | 269 | 1 |
| 03 | 孙风 | 240 | 2 |
| 02 | 钱电 | 210 | 3 |
| 07 | 郑竹 | 187 | 4 |
| 05 | 周梅 | 163 | 5 |
| 04 | 李云 | 100 | 6 |
| 06 | 吴兰 | 65 | 7 |
+-------------+---------+-----------+----------+--+
select t.t_name teacher_name,c.c_name course_name,round(avg(s.s_score),2) avg_score from teacher t join course c on t.t_id = c.t_id join score s on s.c_id = c.c_id group by t.t_name,c.c_name order by avg_score desc;
+---------------+--------------+------------+--+
| teacher_name | course_name | avg_score |
+---------------+--------------+------------+--+
| 张三 | 数学 | 72.67 |
| 王五 | 英语 | 68.5 |
| 李四 | 语文 | 64.5 |
+---------------+--------------+------------+--+
with t as
(select s_id, max(case when c_id = 01 then s_score else 0 end) chinese,max(case when c_id = 02 then s_score else 0 end) math,max(case when c_id = 03 then s_score else 0 end) english,sum(s_score) sum_score ,row_number() over( order by sum(s_score) desc) rank from score group by s_id)
select s.* , chinese,math,english ,sum_score from student s join t on t.s_id = s.s_id where rank between 2 and 3 ;
+---------+-----------+-------------+----------+----------+-------+----------+------------+--+
| s.s_id | s.s_name | s.s_birth | s.s_sex | chinese | math | english | sum_score |
+---------+-----------+-------------+----------+----------+-------+----------+------------+--+
| 03 | 孙风 | 1990-05-20 | 男 | 80 | 80 | 80 | 240 |
| 02 | 钱电 | 1990-12-21 | 男 | 70 | 60 | 80 | 210 |
+---------+-----------+-------------+----------+----------+-------+----------+------------+--+
with score_process as
(select c_id,
sum(case when s_score>=85 and s_score<=100 then 1 else 0 end) Num85_100 , round(sum(case when s_score>=85 and s_score<=100 then 1 else 0 end)/count(s_id),2) Rate85_100,
sum(case when s_score>=70 and s_score<85 then 1 else 0 end) Num70_85 , round(sum(case when s_score>=70 and s_score<85 then 1 else 0 end)/count(s_id),2) Rate70_85,
sum(case when s_score>=60 and s_score<70 then 1 else 0 end) Num60_70 , round(sum(case when s_score>=60 and s_score<70 then 1 else 0 end)/count(s_id),2) Rate60_70,
sum(case when s_score>=0 and s_score<60 then 1 else 0 end) Num0_60 , round(sum(case when s_score>=0 and s_score<60 then 1 else 0 end)/count(s_id),2) Rate0_60
from score group by c_id)
select c.c_name,s.* from course c join score_process s on s.c_id = c.c_id;
+-----------+---------+--------------+---------------+-------------+--------------+-------------+--------------+------------+-------------+--+
| c.c_name | s.c_id | s.num85_100 | s.rate85_100 | s.num70_85 | s.rate70_85 | s.num60_70 | s.rate60_70 | s.num0_60 | s.rate0_60 |
+-----------+---------+--------------+---------------+-------------+--------------+-------------+--------------+------------+-------------+--+
| 语文 | 01 | 0 | 0.0 | 4 | 0.67 | 0 | 0.0 | 2 | 0.33 |
| 数学 | 02 | 3 | 0.5 | 1 | 0.17 | 1 | 0.17 | 1 | 0.17 |
| 英语 | 03 | 2 | 0.33 | 2 | 0.33 | 0 | 0.0 | 2 | 0.33 |
+-----------+---------+--------------+---------------+-------------+--------------+-------------+--------------+------------+-------------+--+
with t as
(select s_id, round(avg(s_score),2) avg_score, RANK() over(order by avg(s_score) desc) rank from score group by s_id)
select s.s_name name, avg_score ,rank from student s join t on t.s_id = s.s_id;
+-------+------------+-------+--+
| name | avg_score | rank |
+-------+------------+-------+--+
| 郑竹 | 93.5 | 1 |
| 赵雷 | 89.67 | 2 |
| 周梅 | 81.5 | 3 |
| 孙风 | 80.0 | 4 |
| 钱电 | 70.0 | 5 |
| 李云 | 33.33 | 6 |
| 吴兰 | 32.5 | 7 |
+-------+------------+-------+--+
with t as
(select *, row_number() over(partition by c_id order by s_score desc ) ranking from score )
select c.c_id c_id,c.c_name course_name,s.s_name stu_name, t.s_score score from t join course c on c.c_id = t.c_id join student s on s.s_id = t.s_id where ranking between 1 and 3;
+-------+--------------+-----------+--------+--+
| c_id | course_name | stu_name | score |
+-------+--------------+-----------+--------+--+
| 01 | 语文 | 孙风 | 80 |
| 01 | 语文 | 赵雷 | 80 |
| 01 | 语文 | 周梅 | 76 |
| 02 | 数学 | 赵雷 | 90 |
| 02 | 数学 | 郑竹 | 89 |
| 02 | 数学 | 周梅 | 87 |
| 03 | 英语 | 赵雷 | 99 |
| 03 | 英语 | 郑竹 | 98 |
| 03 | 英语 | 钱电 | 80 |
+-------+--------------+-----------+--------+--+
with t as
(select c_id,count(s_id) student_num from score where s_score < 60 group by c_id )
select c.c_name course_name, student_num from course c join t on c.c_id= t.c_id;
+--------------+--------------+--+
| course_name | student_num |
+--------------+--------------+--+
| 语文 | 2 |
| 数学 | 1 |
| 英语 | 2 |
+--------------+--------------+--+
with t as
(select s_id,count(c_id) course_num from score group by s_id having course_num =2)
select s.s_id id, s_name name from student s join t on t.s_id = s.s_id;
+-----+-------+--+
| id | name |
+-----+-------+--+
| 05 | 周梅 |
| 06 | 吴兰 |
| 07 | 郑竹 |
+-----+-------+--+
select sum(case when s_sex = '女' then 1 else 0 end) female_num,sum(case when s_sex = '男' then 1 else 0 end) male_num from student ;
+-------------+-----------+--+
| female_num | male_num |
+-------------+-----------+--+
| 4 | 4 |
+-------------+-----------+--+
select * from student where s_name like '%风%';
+---------------+-----------------+------------------+----------------+--+
| student.s_id | student.s_name | student.s_birth | student.s_sex |
+---------------+-----------------+------------------+----------------+--+
| 03 | 孙风 | 1990-05-20 | 男 |
+---------------+-----------------+------------------+----------------+--+
select s_name,s_sex,count(s_id) num from student group by s_name,s_sex having num >= 2;
+---------+--------+------+--+
| s_name | s_sex | num |
+---------+--------+------+--+
+---------+--------+------+--+
with t as
(select *,year(s_birth) birth_year from student)
select t.s_name name from t where birth_year = 1990;
+-------+--+
| name |
+-------+--+
| 赵雷 |
| 钱电 |
| 孙风 |
| 李云 |
| 王菊 |
+-------+--+
select score.c_id, c_name,round(avg(s_score),2) avg_score from score join course on score.c_id= course.c_id group by score.c_id,c_name order by avg_score desc,c_id asc ;
+-------------+---------+------------+--+
| score.c_id | c_name | avg_score |
+-------------+---------+------------+--+
| 02 | 数学 | 72.67 |
| 03 | 英语 | 68.5 |
| 01 | 语文 | 64.5 |
+-------------+---------+------------+--+
with t as
(select s_id,avg(s_score) avg_score from score group by s_id having avg_score>=85)
select s.s_id `学号`, s_name `姓名`, round(avg_score,2 ) `平均分` from student s join t on t.s_id = s.s_id;
+-----+-----+--------+--+
| 学号 | 姓名 | 平均分 |
+-----+-----+--------+--+
| 01 | 赵雷 | 89.67 |
| 07 | 郑竹 | 93.5 |
+-----+-----+--------+--+
select s_name `学生姓名` ,s_score `分数` from course c join score s on c.c_id = s.c_id join student st on st.s_id = s.s_id where c.c_name = '数学' and s_score < 60 ;
+-------+-----+--+
| 学生姓名 | 分数 |
+-------+-----+--+
| 李云 | 30 |
+-------+-----+--+
with t as
(select s_id, max(if(c_id=01 ,s_score, 0 )) chinese,max(if(c_id=02 ,s_score, 0 )) math,max(if(c_id=03 ,s_score, 0 )) english,sum(s_score) sum_score from score group by s_id )
select s_name name,chinese,math,english,sum_score from student s join t on t.s_id = s.s_id;
+-------+----------+-------+----------+------------+--+
| name | chinese | math | english | sum_score |
+-------+----------+-------+----------+------------+--+
| 赵雷 | 80 | 90 | 99 | 269 |
| 钱电 | 70 | 60 | 80 | 210 |
| 孙风 | 80 | 80 | 80 | 240 |
| 李云 | 50 | 30 | 20 | 100 |
| 周梅 | 76 | 87 | 0 | 163 |
| 吴兰 | 31 | 0 | 34 | 65 |
| 郑竹 | 0 | 89 | 98 | 187 |
+-------+----------+-------+----------+------------+--+
select s_name,c_name,s_score from course c join score s on c.c_id = s.c_id join student st on st.s_id = s.s_id where s_score > 70;
+---------+---------+----------+--+
| s_name | c_name | s_score |
+---------+---------+----------+--+
| 赵雷 | 语文 | 80 |
| 赵雷 | 数学 | 90 |
| 赵雷 | 英语 | 99 |
| 钱电 | 英语 | 80 |
| 孙风 | 语文 | 80 |
| 孙风 | 数学 | 80 |
| 孙风 | 英语 | 80 |
| 周梅 | 语文 | 76 |
| 周梅 | 数学 | 87 |
| 郑竹 | 数学 | 89 |
| 郑竹 | 英语 | 98 |
+---------+---------+----------+--+
select s_name,c_name,s_score from course c join score s on c.c_id = s.c_id join student st on st.s_id = s.s_id where s_score < 60 ;
+---------+---------+----------+--+
| s_name | c_name | s_score |
+---------+---------+----------+--+
| 李云 | 语文 | 50 |
| 李云 | 数学 | 30 |
| 李云 | 英语 | 20 |
| 吴兰 | 语文 | 31 |
| 吴兰 | 英语 | 34 |
+---------+---------+----------+--+
select s.s_id `学号`,s_name `姓名` from student st join score s on s.s_id = st.s_id where c_id=01 and s_score >=80;
+-----+-----+--+
| 学号 | 姓名 |
+-----+-----+--+
| 01 | 赵雷 |
| 03 | 孙风 |
+-----+-----+--+
select c_name,count(s.s_id) student_num from course c join score s on s.c_id = c.c_id group by c_name;
+---------+--------------+--+
| c_name | student_num |
+---------+--------------+--+
| 数学 | 6 |
| 英语 | 6 |
| 语文 | 6 |
+---------+--------------+--+
select st.*,c_name,s_score from course c join score s on c.c_id = s.c_id join teacher t on t.t_id = c.t_id join student st on st.s_id=s.s_id where t_name='张三' order by s_score desc limit 1;
+----------+------------+-------------+-----------+---------+----------+--+
| st.s_id | st.s_name | st.s_birth | st.s_sex | c_name | s_score |
+----------+------------+-------------+-----------+---------+----------+--+
| 01 | 赵雷 | 1990-01-01 | 男 | 数学 | 90 |
+----------+------------+-------------+-----------+---------+----------+--+
select distinct s1.* from score s1,score s2 where s1.c_id <>s2.c_id and s1.s_score=s2.s_score ;
+----------+----------+-------------+--+
| s1.s_id | s1.c_id | s1.s_score |
+----------+----------+-------------+--+
| 01 | 01 | 80 |
| 02 | 03 | 80 |
| 03 | 01 | 80 |
| 03 | 02 | 80 |
| 03 | 03 | 80 |
+----------+----------+-------------+--+
with t as
(select c_name,s_name,s_score, row_number() over(partition by c_name order by s_score desc) rank from student s join score sc on sc.s_id=s.s_id join course c on c.c_id=sc.c_id)
select * from t where rank between 1 and 3;
+-----------+-----------+------------+---------+--+
| t.c_name | t.s_name | t.s_score | t.rank |
+-----------+-----------+------------+---------+--+
| 数学 | 赵雷 | 90 | 1 |
| 数学 | 郑竹 | 89 | 2 |
| 数学 | 周梅 | 87 | 3 |
| 英语 | 赵雷 | 99 | 1 |
| 英语 | 郑竹 | 98 | 2 |
| 英语 | 孙风 | 80 | 3 |
| 语文 | 孙风 | 80 | 1 |
| 语文 | 赵雷 | 80 | 2 |
| 语文 | 周梅 | 76 | 3 |
+-----------+-----------+------------+---------+--+
– 要求输出课程号和选修人数,查询结果按人数降序排列,若人数相同,按课程号升序排列
select c_id,count(s_id) num from score group by c_id having num > 5 order by num desc ,c_id asc;
+-------+------+--+
| c_id | num |
+-------+------+--+
| 01 | 6 |
| 02 | 6 |
| 03 | 6 |
+-------+------+--+
select s_id,count(c_id) course_num from score group by s_id having course_num>=2;
+-------+-------------+--+
| s_id | course_num |
+-------+-------------+--+
| 01 | 3 |
| 02 | 3 |
| 03 | 3 |
| 04 | 3 |
| 05 | 2 |
| 06 | 2 |
| 07 | 2 |
+-------+-------------+--+
with t as
(select count(c_id) sum_course from course),
t1 as
(select s_id,count(c_id) course_num from score group by s_id)
select s.* from t1 join t join student s on s.s_id=t1.s_id where sum_course=course_num;
+---------+-----------+-------------+----------+--+
| s.s_id | s.s_name | s.s_birth | s.s_sex |
+---------+-----------+-------------+----------+--+
| 01 | 赵雷 | 1990-01-01 | 男 |
| 02 | 钱电 | 1990-12-21 | 男 |
| 03 | 孙风 | 1990-05-20 | 男 |
| 04 | 李云 | 1990-08-06 | 男 |
+---------+-----------+-------------+----------+--+
select *, floor((datediff(current_date,s_birth))/365) age from student;
+---------------+-----------------+------------------+----------------+------+--+
| student.s_id | student.s_name | student.s_birth | student.s_sex | age |
+---------------+-----------------+------------------+----------------+------+--+
| 01 | 赵雷 | 1990-01-01 | 男 | 29 |
| 02 | 钱电 | 1990-12-21 | 男 | 28 |
| 03 | 孙风 | 1990-05-20 | 男 | 29 |
| 04 | 李云 | 1990-08-06 | 男 | 29 |
| 05 | 周梅 | 1991-12-01 | 女 | 28 |
| 06 | 吴兰 | 1992-03-01 | 女 | 27 |
| 07 | 郑竹 | 1989-07-01 | 女 | 30 |
| 08 | 王菊 | 1990-01-20 | 女 | 29 |
+---------------+-----------------+------------------+----------------+------+--+
select * from student where weekofyear(s_birth)=weekofyear(current_date);
+---------------+-----------------+------------------+----------------+--+
| student.s_id | student.s_name | student.s_birth | student.s_sex |
+---------------+-----------------+------------------+----------------+--+
+---------------+-----------------+------------------+----------------+--+
select * from student where weekofyear(s_birth)=weekofyear(current_date)+1;
+---------------+-----------------+------------------+----------------+--+
| student.s_id | student.s_name | student.s_birth | student.s_sex |
+---------------+-----------------+------------------+----------------+--+
| 02 | 钱电 | 1990-12-21 | 男 |
+---------------+-----------------+------------------+----------------+--+
select * from student where month(current_date) = month(s_birth) ;
+---------------+-----------------+------------------+----------------+--+
| student.s_id | student.s_name | student.s_birth | student.s_sex |
+---------------+-----------------+------------------+----------------+--+
| 02 | 钱电 | 1990-12-21 | 男 |
| 05 | 周梅 | 1991-12-01 | 女 |
+---------------+-----------------+------------------+----------------+--+
select * from student where month(s_birth) = 12;
+---------------+-----------------+------------------+----------------+--+
| student.s_id | student.s_name | student.s_birth | student.s_sex |
+---------------+-----------------+------------------+----------------+--+
| 02 | 钱电 | 1990-12-21 | 男 |
| 05 | 周梅 | 1991-12-01 | 女 |
+---------------+-----------------+------------------+----------------+--+