sql语句练习50题(Mysql版)

表名和字段
–1.学生表
Student(s_id,s_name,s_birth,s_sex) –学生编号,学生姓名, 出生年月,学生性别
–2.课程表
Course(c_id,c_name,t_id) – –课程编号, 课程名称, 教师编号
–3.教师表
Teacher(t_id,t_name) –教师编号,教师姓名
–4.成绩表
Score(s_id,c_id,s_score) –学生编号,课程编号,分数
测试数据

 --建表 --学生表 CREATE TABLE `Student`(
     `s_id` ),
     `s_name` ) NOT NULL DEFAULT '',
     `s_birth` ) NOT NULL DEFAULT '',
     `s_sex` ) NOT NULL DEFAULT '',
     PRIMARY KEY(`s_id`)
 ); --课程表 CREATE TABLE `Course`(
     `c_id`  ),
     `c_name` ) NOT NULL DEFAULT '',
     `t_id` ) NOT NULL,
     PRIMARY KEY(`c_id`)
 ); --教师表 CREATE TABLE `Teacher`(
     `t_id` ),
     `t_name` ) NOT NULL DEFAULT '',
     PRIMARY KEY(`t_id`)
 ); --成绩表 CREATE TABLE `Score`(
     `s_id` ),
     `c_id`  ),
     `s_score` ),
     PRIMARY KEY(`s_id`,`c_id`)
 ); --插入学生表测试数据 insert into Student values('01' , '赵雷' , '1990-01-01' , '男'); insert into Student values('02' , '钱电' , '1990-12-21' , '男'); insert into Student values('03' , '孙风' , '1990-05-20' , '男'); insert into Student values('04' , '李云' , '1990-08-06' , '男'); insert into Student values('05' , '周梅' , '1991-12-01' , '女'); insert into Student values('06' , '吴兰' , '1992-03-01' , '女'); insert into Student values('07' , '郑竹' , '1989-07-01' , '女'); insert into Student values('08' , '王菊' , '1990-01-20' , '女'); --课程表测试数据 insert into Course values('01' , '语文' , '02'); insert into Course values('02' , '数学' , '01'); insert into Course values('03' , '英语' , '03'); --教师表测试数据 insert into Teacher values('01' , '张三'); insert into Teacher values('02' , '李四'); insert into Teacher values('03' , '王五'); --成绩表测试数据 insert into Score values('01' , '01' , 80); insert into Score values('01' , '02' , 90); insert into Score values('01' , '03' , 99); insert into Score values('02' , '01' , 70); insert into Score values('02' , '02' , 60); insert into Score values('02' , '03' , 80); insert into Score values('03' , '01' , 80); insert into Score values('03' , '02' , 80); insert into Score values('03' , '03' , 80); insert into Score values('04' , '01' , 50); insert into Score values('04' , '02' , 30); insert into Score values('04' , '03' , 20); insert into Score values('05' , '01' , 76); insert into Score values('05' , '02' , 87); insert into Score values('06' , '01' , 31); insert into Score values('06' , '03' , 34); insert into Score values('07' , '02' , 89); insert into Score values('07' , '03' , 98);

练习题和sql语句

-- 1、查询"01"课程比"02"课程成绩高的学生的信息及课程分数
select a.* ,b.s_score as 01_score,c.s_score as 02_score from
    student a
    '
    ' or c.c_id = NULL where b.s_score>c.s_score

-- 2、查询"01"课程比"02"课程成绩低的学生的信息及课程分数
select a.* ,b.s_score as 01_score,c.s_score as 02_score from
    student a ' or b.c_id=NULL
     ' where b.s_score<c.s_score

-- 3、查询平均成绩大于等于60分的同学的学生编号和学生姓名和平均成绩
) as avg_score from
    student b
    join score a on b.s_id = a.s_id
    ); 

-- 4、查询平均成绩小于60分的同学的学生编号和学生姓名和平均成绩 -- (包括有成绩的和无成绩的)
) as avg_score from
    student b
    left join score a on b.s_id = a.s_id
    )
    union
 as avg_score from
    student a
    where a.s_id not in (
                select distinct s_id from score); 

-- 5、查询所有同学的学生编号、学生姓名、选课总数、所有课程的总成绩
select a.s_id,a.s_name,count(b.c_id) as sum_course,sum(b.s_score) as sum_score from
    student a
    left join score b on a.s_id=b.s_id
    GROUP BY a.s_id,a.s_name;
-- 6、查询"李"姓老师的数量
select count(t_id) from teacher where t_name like '李%';
-- 7、查询学过"张三"老师授课的同学的信息
select a.* from
    student a
    join score b on a.s_id=b.s_id where b.c_id in(
        select c_id from course where t_id =(
            select t_id from teacher where t_name = '张三'));
-- 8、查询没学过"张三"老师授课的同学的信息
select * from
    student c
    where c.s_id not in(
        select a.s_id from student a join score b on a.s_id=b.s_id where b.c_id in(
            select c_id from course where t_id =(
                select t_id from teacher where t_name = '张三')));
-- 9、查询学过编号为"01"并且也学过编号为"02"的课程的同学的信息
select a.* from
    student a,score b,score c
    '; 

-- 10、查询学过编号为"01"但是没有学过编号为"02"的课程的同学的信息
select a.* from
    student a
    ')

-- 11、查询没有学全所有课程的同学的信息
select s.* from
    student s where s.s_id in(
        select s_id from score where s_id not in(
            select a.s_id from score a
                '
                '
            '))

-- 12、查询至少有一门课与学号为"01"的同学所学相同的同学的信息
select * from student where s_id in(
    ')
    );
-- 13、查询和"01"号的同学学习的课程完全相同的其他同学的信息
select a.* from student a where a.s_id in(
    ')
    group by s_id
    )) '));
-- 14、查询没学过"张三"老师讲授的任一门课程的学生姓名
select a.s_name from student a where a.s_id not in (
    select s_id from score where c_id =
                (select c_id from course where t_id =(
                    select t_id from teacher where t_name = '张三'))
                group by s_id);
-- 15、查询两门及其以上不及格课程的同学的学号，姓名及其平均成绩
select a.s_id,a.s_name,ROUND(AVG(b.s_score)) from
    student a
    left join score b on a.s_id = b.s_id
    where a.s_id in(
             ))
    GROUP BY a.s_id,a.s_name

-- 16、检索"01"课程分数小于60，按分数降序排列的学生信息
select a.*,b.c_id,b.s_score from
    student a,score b
     ORDER BY b.s_score DESC;
-- 17、按平均成绩从高到低显示所有学生的所有课程的成绩以及平均成绩
') as 语文,
                (') as 数学,
                (') as 英语,
            ) as 平均分 from score a  GROUP BY a.s_id ORDER BY 平均分 DESC; 

-- 18.查询各科成绩最高分、最低分和平均分：以如下形式显示：课程ID，课程name，最高分，最低分，平均分，及格率，中等率，优良率，优秀率 --及格为>=60，中等为：70-80，优良为：80-90，优秀为：>=90
),
         ) as 及格率,
          ) as 中等率,
          ) as 优良率,
         ) as 优秀率
    from score a left join course b on a.c_id = b.c_id GROUP BY a.c_id,b.c_name

-- 19、按各科成绩进行排序，并显示排名(实现不完全)
-- mysql没有rank函数
select a.s_id,a.c_id,
         as i保留排名,
        @k:=(case when @score=a.s_score then @k else @i end) as rank不保留排名,
        @score:=a.s_score as score
    from (
        ' GROUP BY s_id,c_id,s_score ORDER BY s_score DESC
)a,(,,)s
    union
    select a.s_id,a.c_id,
         as i,
        @k:=(case when @score=a.s_score then @k else @i end) as rank,
        @score:=a.s_score as score
    from (
        ' GROUP BY s_id,c_id,s_score ORDER BY s_score DESC
)a,(,,)s
    union
    select a.s_id,a.c_id,
         as i,
        @k:=(case when @score=a.s_score then @k else @i end) as rank,
        @score:=a.s_score as score
    from (
        ' GROUP BY s_id,c_id,s_score ORDER BY s_score DESC
)a,(,,)s

-- 20、查询学生的总成绩并进行排名
select a.s_id,
     as i,
    @k:=(case when @score=a.sum_score then @k else @i end) as rank,
    @score:=a.sum_score as score
from (select s_id,SUM(s_score) as sum_score from score GROUP BY s_id ORDER BY sum_score DESC)a,
    (,,)s

-- 21、查询不同老师所教不同课程平均分从高到低显示
    ) as avg_score from course a
        left join score b on a.c_id=b.c_id
        left join teacher c on a.t_id=c.t_id
        GROUP BY a.c_id,a.t_id,c.t_name ORDER BY avg_score DESC; 

-- 22、查询所有课程的成绩第2名到第3名的学生信息及该课程成绩
select d.*,c.排名,c.s_score,c.c_id from (
                 )s '
            )c
            left join student d on c.s_id=d.s_id

            UNION
            select d.*,c.排名,c.s_score,c.c_id from (
                 )s '
            )c
            left join student d on c.s_id=d.s_id

            UNION
            select d.*,c.排名,c.s_score,c.c_id from (
                 )s '
            )c
            left join student d on c.s_id=d.s_id
             ; 

-- 23、统计各科成绩各分数段人数：课程编号,课程名称,[100-85],[85-70],[70-60],[0-60]及所占百分比 select distinct f.c_name,a.c_id,b.`85-100`,b.百分比,c.`70-85`,c.百分比,d.`60-70`,d.百分比,e.`0-60`,e.百分比 from score a
                    `,
                                                ) as 百分比
                                from score GROUP BY c_id)b on a.c_id=b.c_id
                    `,
                                                ) as 百分比
                                from score GROUP BY c_id)c on a.c_id=c.c_id
                    `,
                                                ) as 百分比
                                from score GROUP BY c_id)d on a.c_id=d.c_id
                    `,
                                                ) as 百分比
                                from score GROUP BY c_id)e on a.c_id=e.c_id
                left join course f on a.c_id = f.c_id

-- 24、查询学生平均成绩及其名次 

select a.s_id,
                 as '不保留空缺排名',
                @k:=(case when @avg_score=a.avg_s then @k else @i end) as '保留空缺排名',
                @avg_score:=avg_s as '平均分'
        ) ,,)b; 

-- 25、查询各科成绩前三名的记录 -- 1.选出b表比a表成绩大的所有组 -- 2.选出比当前id成绩大的 小于三个的
select a.s_id,a.c_id,a.s_score from score a
            left join score b on a.c_id = b.c_id and a.s_score<b.s_score

            ORDER BY a.c_id,a.s_score DESC

-- 26、查询每门课程被选修的学生数
select c_id,count(s_id) from score a GROUP BY c_id

-- 27、查询出只有两门课程的全部学生的学号和姓名
select s_id,s_name from student where s_id in(
                ); 

-- 28、查询男生、女生人数
select s_sex,COUNT(s_sex) as 人数  from student GROUP BY s_sex

-- 29、查询名字中含有"风"字的学生信息
select * from student where s_name like '%风%'; 

-- 30、查询同名同性学生名单，并统计同名人数
select a.s_name,a.s_sex,count(*) from student a  JOIN
                    student b on a.s_id !=b.s_id and a.s_name = b.s_name and a.s_sex = b.s_sex
        GROUP BY a.s_name,a.s_sex

-- 31、查询1990年出生的学生名单
select s_name from student where s_birth like '1990%'

-- 32、查询每门课程的平均成绩，结果按平均成绩降序排列，平均成绩相同时，按课程编号升序排列
) as avg_score from score GROUP BY c_id ORDER BY avg_score DESC,c_id ASC

-- 33、查询平均成绩大于等于85的所有学生的学号、姓名和平均成绩
) as avg_score from score a

-- 34、查询课程名称为"数学"，且分数低于60的学生姓名和分数
select a.s_name,b.s_score from score b LEFT JOIN student a on a.s_id=b.s_id where b.c_id=(

-- 35、查询所有学生的课程及分数情况；
select a.s_id,a.s_name,
                     end) as '语文',
                     end) as '数学',
                     end) as '英语',
                    SUM(b.s_score) as  '总分'
        from student a left join score b on a.s_id = b.s_id
        left join course c on b.c_id = c.c_id
        GROUP BY a.s_id,a.s_name

 -- 36、查询任何一门课程成绩在70分以上的姓名、课程名称和分数；
select a.s_name,b.c_name,c.s_score from course b left join score c on b.c_id = c.c_id

-- 37、查询不及格的课程
select a.s_id,a.c_id,b.c_name,a.s_score from score a left join course b on a.c_id = b.c_id

--38、查询课程编号为01且课程成绩在80分以上的学生的学号和姓名；
select a.s_id,b.s_name from score a LEFT JOIN student b on a.s_id = b.s_id

-- 39、求每门课程的学生人数
select count(*) from score GROUP BY c_id; 

-- 40、查询选修"张三"老师所授课程的学生中，成绩最高的学生信息及其成绩 -- 查询老师id
select c_id from course c,teacher d where c.t_id=d.t_id and d.t_name='张三'
        -- 查询最高分（可能有相同分数）
        '
        -- 查询信息
        select a.*,b.s_score,b.c_id,c.c_name from student a
            LEFT JOIN score b on a.s_id = b.s_id
            LEFT JOIN course c on b.c_id=c.c_id
            where b.c_id =(select c_id from course c,teacher d where c.t_id=d.t_id and d.t_name='张三')
            ')

-- 41、查询不同课程成绩相同的学生的学生编号、课程编号、学生成绩
    select DISTINCT b.s_id,b.c_id,b.s_score from score a,score b where a.c_id != b.c_id and a.s_score = b.s_score

-- 42、查询每门功成绩最好的前两名
-- 牛逼的写法
select a.s_id,a.c_id,a.s_score from score a
        )  ORDER BY a.c_id

-- 43、统计每门课程的学生选修人数（超过5人的课程才统计）。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
 ORDER BY total,c_id ASC

-- 44、检索至少选修两门课程的学生学号 

-- 45、查询选修了全部课程的学生信息
select * from student where s_id in(
            select s_id from score GROUP BY s_id HAVING count(*)=(select count(*) from course))

--46、查询各学生的年龄
    -- 按照出生日期来算，当前月日 < 出生年月的月日则，年龄减一

    select s_birth,(DATE_FORMAT(NOW(),'%Y')-DATE_FORMAT(s_birth,'%Y') -
                (  end)) as age
        from student; 

-- 47、查询本周过生日的学生
select * from student where WEEK(DATE_FORMAT(NOW(),'%Y%m%d'))=WEEK(s_birth)
    select * from student where YEARWEEK(s_birth)=YEARWEEK(DATE_FORMAT(NOW(),'%Y%m%d'))

    select WEEK(DATE_FORMAT(NOW(),'%Y%m%d'))

-- 48、查询下周过生日的学生
     =WEEK(s_birth)

-- 49、查询本月过生日的学生

    select * from student where MONTH(DATE_FORMAT(NOW(),'%Y%m%d')) =MONTH(s_birth)

-- 50、查询下月过生日的学生
     =MONTH(s_birth)