引用自https://www.cnblogs.com/kangxinxin/p/11585935.html
CREATE DATABASE test_11_28;
-- 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 VARCHAR(20),
s_name VARCHAR(20) NOT NULL DEFAULT '',
s_birth VARCHAR(20) NOT NULL DEFAULT '',
s_sex VARCHAR(10) NOT NULL DEFAULT '',
PRIMARY KEY(s_id)
);
-- 课程表
CREATE TABLE Course(
c_id VARCHAR(20),
c_name VARCHAR(20) NOT NULL DEFAULT '',
t_id VARCHAR(20) NOT NULL,
PRIMARY KEY(c_id)
);
-- 教师表
CREATE TABLE Teacher(
t_id VARCHAR(20),
t_name VARCHAR(20) NOT NULL DEFAULT '',
PRIMARY KEY(t_id)
);
-- 成绩表
CREATE TABLE Score(
s_id VARCHAR(20),
c_id VARCHAR(20),
s_score INT(3),
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);
-- 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 s., a.c_id, a.s_score, b.c_id, b.s_score
FROM Student s
JOIN (SELECT *
FROM Score
WHERE c_id = '01') a
ON s.s_id = a.s_id
JOIN (SELECT * FROM Score
WHERE c_id = '02') b
ON s.s_id = b.s_id
WHERE a.s_score > b.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 s., a.c_id, a.s_score, b.c_id, b.s_score
FROM Student s
JOIN (SELECT *
FROM Score
WHERE c_id = '01') a
ON s.s_id = a.s_id
JOIN (SELECT * FROM Score
WHERE c_id = '02') b
ON s.s_id = b.s_id
WHERE a.s_score < b.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
SELECT s.s_id, s.s_name, AVG(sc.s_score)
FROM Score sc
JOIN Student s
ON sc.s_id = s.s_id
GROUP BY s_id
HAVING AVG(s_score) >= 60
-- 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)
SELECT s.s_id, s.s_name, AVG(sc.s_score)
FROM Student s
LEFT JOIN Score sc
ON sc.s_id = s.s_id
GROUP BY s_id
HAVING AVG(IFNULL(s_score, 0)) <= 60
-- 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 s.s_id, s.s_name, COUNT(sc.c_id) AS 选课总数,SUM(sc.s_score) AS 总成绩
FROM Student s
LEFT JOIN score sc
ON s.s_id = sc.s_id
GROUP BY s.s_id
-- 6、查询"李"姓老师的数量
SELECT COUNT()
FROM Teacher
WHERE t_name REGEXP '^李';
-- 7、查询学过"张三"老师授课的同学的信息
SELECT s.
FROM Student s
JOIN Score sc
ON s.s_id = sc.s_id
JOIN Course c
ON sc.c_id = c.c_id
JOIN Teacher t
ON c.t_id = t.t_id
WHERE t.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 st
WHERE st.s_id NOT IN
(SELECT s.s_id
FROM Student s
JOIN Score sc
ON s.s_id = sc.s_id
JOIN Course c
ON sc.c_id = c.c_id
JOIN Teacher t
ON c.t_id = t.t_id
WHERE t.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 *
FROM Student
WHERE s_id IN
(SELECT s_id
FROM Score
WHERE c_id = '01'
AND s_id IN
(SELECT s_id
FROM score
WHERE c_id = '02'));
-- 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 *
FROM Student
WHERE s_id IN
(SELECT s_id
FROM Score
WHERE c_id = '01'
AND s_id NOT IN
(SELECT s_id
FROM score
WHERE c_id = '02'));
-- 11、查询没有学全所有课程的同学的信息
-- select *
-- from Student
-- where s_id not in
-- (select s_id
-- from Score
-- where c_id = '01'
-- and s_id in
-- (select s_id
-- from score
-- where c_id = '02'
-- and s_id in
-- (select s_id
-- from Score
-- where c_id = '03')));
######################################################
SELECT s_id
FROM Score
GROUP BY s_id
HAVING COUNT() < (
SELECT COUNT()
FROM Course)
-- 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 DISTINCT s.*
FROM Score sc
JOIN Student s
ON sc.s_id = s.s_id
WHERE c_id IN(
SELECT c_id
FROM Score
WHERE s_id = '01')
-- 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 *
FROM score sc
JOIN(SELECT s_id,c_id
FROM score
WHERE s_id = '01') a
ON sc.c_id = a.c_id
#####################################################
SELECT st.* FROM student st
LEFT JOIN score sc ON sc.s_id=st.s_id
GROUP BY st.s_id
HAVING GROUP_CONCAT(sc.c_id) =
(
SELECT GROUP_CONCAT(sc2.c_id) FROM student st2
LEFT JOIN score sc2 ON sc2.s_id=st2.s_id
WHERE st2.s_id ='01'
)
-- 题意转换为选课数和 01 号学生一样，且选的课不在 01 号学生未选的课中
#选课数和 01 号学生一样
SELECT DISTINCT sc.s_id
FROM Score sc
JOIN (SELECT s_id
FROM Score
GROUP BY s_id
HAVING COUNT() = (
SELECT COUNT()
FROM Score
WHERE s_id = '01')) a
ON sc.s_id = a.s_id
WHERE c_id NOT IN (
SELECT c_id
FROM Course
WHERE c_id NOT IN(
SELECT c_id
FROM Score
WHERE s_id = '01'))
###########################################################
-- 14、查询没学过"张三"老师讲授的任一门课程的学生姓名
SELECT *
FROM Student
WHERE s_id NOT IN
(
SELECT s_id
FROM Score
WHERE c_id IN
(SELECT c_id
FROM Teacher t
JOIN Course c
ON t.t_id = c.c_id
WHERE t.t_name = '张三'));
-- 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 s.s_id,s.s_name, AVG(sc.s_score)
FROM Student s
JOIN Score sc
ON s.s_id = sc.s_id
WHERE s.s_id IN
(SELECT s_id
FROM Score
WHERE s_score < 60
GROUP BY s_id
HAVING COUNT() >= 2)
GROUP BY s.s_id;
-- 16、检索"01"课程分数小于60，按分数降序排列的学生信息
SELECT s.
FROM Score sc
JOIN Student s
ON sc.s_id = s.s_id
WHERE sc.c_id = '01'
AND sc.s_score < '60'
ORDER BY sc.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
############################
-- 方法一 思路：分别查询一个课程号每个学生的成绩（共三次），再与student表连接
SELECT s.s_id, s.s_name,sc1.s_score AS 语文, sc2.s_score AS 数学, sc3.s_score AS 英语,AVG(sc.s_score) AS 平均成绩
FROM Student s
LEFT JOIN Score sc1 ON s.s_id = sc1.s_id AND sc1.c_id = '01'
LEFT JOIN score sc2 ON s.s_id = sc2.s_id AND sc2.c_id = '02'
LEFT JOIN score sc3 ON s.s_id = sc3.s_id AND sc3.c_id = '03'
LEFT JOIN score sc ON s.s_id = sc.s_id
GROUP BY s.s_id
ORDER BY 平均成绩 DESC
-- 方法二 思路：但是要把列转换为行的操作，都可以在select后面加子查询
-- 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
-- 方法一
SELECT c.c_id AS 课程ID, c.c_name AS 课程name,MAX(s_score) AS 最高分,MIN(s_score) AS 最低分,AVG(s_score) AS 平均分, COUNT() AS num,
SUM(CASE WHEN sc.s_score>=60 THEN 1 ELSE 0 END)/COUNT() AS 及格率,
SUM(CASE WHEN sc.s_score>=70 AND sc.s_score < 80 THEN 1 ELSE 0 END)/COUNT() AS 中等率,
SUM(CASE WHEN sc.s_score>=80 AND sc.s_score < 90 THEN 1 ELSE 0 END)/COUNT() AS 优良率,
SUM(CASE WHEN sc.s_score>=90 THEN 1 ELSE 0 END)/COUNT(*) AS 优秀率
FROM Score sc
LEFT JOIN Course c ON sc.c_id = c.c_id GROUP BY c.c_id
-- 方法二
SELECT a., b.bj/num AS 及格率, c.czd/num AS 中等率, d.dyl/num AS 优良率, e.eyx/num AS 优秀率
FROM (SELECT c.c_id AS 课程ID, c.c_name AS 课程name,MAX(s_score) AS 最高分,MIN(s_score) AS 最低分,AVG(s_score) AS 平均分, COUNT() AS num
FROM Score sc
LEFT JOIN Course c ON sc.c_id = c.c_id GROUP BY c.c_id) a
LEFT JOIN (SELECT c_id, COUNT() AS bj FROM Score WHERE s_score >= 60 GROUP BY c_id) b ON a.课程ID = b.c_id
LEFT JOIN(SELECT c_id, COUNT(IFNULL(c_id, 0)) AS czd FROM Score WHERE s_score >= 70 AND s_score < 80 GROUP BY c_id) c ON a.课程ID = c.c_id
LEFT JOIN (SELECT c_id, COUNT(IFNULL(c_id, 0)) AS dyl FROM Score WHERE s_score >= 80 AND s_score < 90 GROUP BY c_id) d ON a.课程ID = d.c_id
LEFT JOIN (SELECT c_id, COUNT(IFNULL(c_id, 0)) AS eyx FROM Score WHERE s_score >= 90 GROUP BY c_id) e ON a.课程ID = e.c_id
#############################################
19、按各科成绩进行排序，并显示 排名
#############################################
SELECT sc1.,COUNT(sc2.s_score) AS rank
FROM Score sc1
LEFT JOIN Score sc2
ON sc1.c_id = sc2.c_id
AND sc1.s_score <= sc2.s_score
GROUP BY sc1.c_id, sc1.s_id
ORDER BY sc1.c_id, rank
-- 20、查询学生的总成绩并进行排名
SELECT a.*, COUNT(b.s_id) AS rank
FROM (SELECT s_id,SUM(sc.s_score) AS s
FROM Score sc
GROUP BY sc.s_id) a
LEFT JOIN (SELECT s_id,SUM(sc.s_score) AS s
FROM Score sc
GROUP BY sc.s_id) b
ON a.s<=b.s
GROUP BY a.s_id
ORDER BY rank
-- 21、查询不同老师所教不同课程平均分从高到低显示
SELECT t.t_name, c.c_name, AVG(sc.s_score)
FROM Teacher t
JOIN Course c
ON t.t_id = c.t_id
JOIN score sc
ON c.c_id = sc.c_id
GROUP BY c.c_id
ORDER BY AVG(s_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
方案一：（由于课程较少，可以采用这种方法，但是如果课程数多就不可以，应该采用 SQL 循环，
-- 如果题目要求中没有声明选取课程几，代码中就不应该出现 ’01‘，’02‘，’03’ 这样的课程。）
SELECT * FROM (
SELECT s.,c., s_score
FROM Score sc
JOIN course c
ON sc.c_id = c.c_id
JOIN student s
ON s.s_id = sc.s_id
WHERE c.c_id = '01'
ORDER BY s_score DESC
LIMIT 1,2) a
UNION ALL
SELECT * FROM(
SELECT s.,c., s_score
FROM Score sc
JOIN course c
ON sc.c_id = c.c_id
JOIN student s
ON s.s_id = sc.s_id
WHERE c.c_id = '02'
ORDER BY s_score DESC
LIMIT 1,2) b
UNION ALL
SELECT * FROM (
SELECT s.,c., s_score
FROM Score sc
JOIN course c
ON sc.c_id = c.c_id
JOIN student s
ON s.s_id = sc.s_id
WHERE c.c_id = '03'
ORDER BY s_score DESC
LIMIT 1,2) c
###############################################
-- 方案二
-- 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 c.c_id,c.c_name
,((SELECT COUNT(1) FROM score sc WHERE sc.c_id=c.c_id AND sc.s_score<=100 AND sc.s_score>80)/(SELECT COUNT(1) FROM score sc WHERE sc.c_id=c.c_id )) "100-85"
,((SELECT COUNT(1) FROM score sc WHERE sc.c_id=c.c_id AND sc.s_score<=85 AND sc.s_score>70)/(SELECT COUNT(1) FROM score sc WHERE sc.c_id=c.c_id )) "85-70"
,((SELECT COUNT(1) FROM score sc WHERE sc.c_id=c.c_id AND sc.s_score<=70 AND sc.s_score>60)/(SELECT COUNT(1) FROM score sc WHERE sc.c_id=c.c_id )) "70-60"
,((SELECT COUNT(1) FROM score sc WHERE sc.c_id=c.c_id AND sc.s_score<=60 AND sc.s_score>=0)/(SELECT COUNT(1) FROM score sc WHERE sc.c_id=c.c_id )) "60-0"
FROM course c ORDER BY c.c_id
-- 24、查询学生平均成绩及其名次
SELECT a.s_id, COUNT(b.s_id)
FROM (
SELECT s_id, AVG(s_score) AS av
FROM score
GROUP BY s_id) a
JOIN (SELECT s_id, AVG(s_score) AS av
FROM score
GROUP BY s_id) b
ON a.av <= b.av
GROUP BY a.s_id
-- 25、查询各科成绩前三名的记录
SELECT * FROM (
SELECT s., c., sc.s_score
FROM student s
JOIN score sc ON s.s_id = sc.s_id
JOIN course c ON c.c_id = sc.c_id
WHERE c.c_id = '01'
ORDER BY sc.s_score DESC
LIMIT 0,3) a
UNION ALL
SELECT * FROM (
SELECT s., c., sc.s_score
FROM student s
JOIN score sc ON s.s_id = sc.s_id
JOIN course c ON c.c_id = sc.c_id
WHERE c.c_id = '02'
ORDER BY sc.s_score DESC
LIMIT 0,3) b
UNION ALL
SELECT * FROM (
SELECT s., c., sc.s_score
FROM student s
JOIN score sc ON s.s_id = sc.s_id
JOIN course c ON c.c_id = sc.c_id
WHERE c.c_id = '03'
ORDER BY sc.s_score DESC
LIMIT 0,3) c
-- 26、查询每门课程被选修的学生数
SELECT c.c_name, COUNT(sc.s_id)
FROM course c
LEFT JOIN score sc ON sc.c_id = c.c_id
GROUP BY c.c_id
-- 27、查询出只有两门课程的全部学生的学号和姓名
SELECT sc.s_id, s.s_name
FROM score sc
JOIN student s ON sc.s_id = s.s_id
GROUP BY s.s_id
HAVING COUNT() = 2
-- 28、查询男生、女生人数
SELECT s.s_sex,COUNT()
FROM Student s
GROUP BY s.s_sex
-- 29、查询名字中含有"风"字的学生信息
SELECT *
FROM Student s
WHERE s.s_name LIKE ***%'
-- 30、查询同名同性学生名单，并统计同名人数
SELECT s1.s_id, s1.s_name, s1.s_sex,COUNT()
FROM student s1
JOIN student s2 ON s1.s_name = s2.s_name
AND s1.s_id != s2.s_id
AND s1.s_sex = s2.s_sex
GROUP BY s1.s_name
HAVING COUNT() > 1
SELECT s_id, s_name, COUNT()
FROM student
GROUP BY s_name
HAVING COUNT() > 1
SELECT st.,COUNT() FROM student st GROUP BY st.s_name,st.s_sex HAVING COUNT(*)>1
-- 31、查询1990年出生的学生名单
SELECT *
FROM student
WHERE YEAR(s_birth) = 1990
SELECT * 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
SELECT c_id, AVG(s_score) AS av
FROM score
GROUP BY c_id
ORDER BY av DESC, c_id
-- 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
SELECT s.s_id, s_name, AVG(s_score) AS av
FROM score sc
JOIN Student s ON sc.s_id = s.s_id
GROUP BY s.s_id
HAVING av >= 85
-- 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 s.s_name, sc.s_score
FROM course c
JOIN Score sc ON c.c_id = sc.c_id
JOIN Student s ON s.s_id = sc.s_id
WHERE c.c_name = '数学'
AND sc.s_score < 60
-- 35、查询所有学生的课程及分数情况；
SELECT s.s_name, c.c_name, sc.s_score
FROM score sc
JOIN course c ON sc.c_id = c.c_id
RIGHT JOIN student s ON sc.s_id = s.s_id
-- 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 s.s_name, c.c_name, sc.s_score
FROM score sc
JOIN student s ON sc.s_id = s.s_id
JOIN course c ON sc.c_id = c.c_id
AND sc.s_score > 70
-- 37、查询不及格的课程
SELECT s.s_name, c.c_name, sc.s_score
FROM score sc
JOIN student s ON sc.s_id = s.s_id
JOIN course c ON sc.c_id = c.c_id
WHERE sc.s_score < 60
-- 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 s.s_name, c.c_name, sc.s_score
FROM score sc
JOIN student s ON sc.s_id = s.s_id
JOIN course c ON sc.c_id = c.c_id
WHERE c.c_id = '01'
AND sc.s_score > 80
-- 39、求每门课程的学生人数
SELECT c.c_name, COUNT(sc.s_id)
FROM score sc
JOIN course c ON sc.c_id = c.c_id
GROUP BY c.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
SELECT s.s_name, c.c_name, MAX(sc.s_score)
FROM score sc
JOIN student s ON sc.s_id = s.s_id
JOIN course c ON sc.c_id = c.c_id
JOIN teacher t ON c.t_id = t.t_id
WHERE t.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 sc1.*
FROM score sc1
JOIN score sc2 ON sc1.s_score = sc2.s_score
AND sc1.c_id != sc2.c_id
AND sc1.s_id != sc2.s_id
SELECT st.s_id,st.s_name,sc.c_id,sc.s_score FROM student st
LEFT JOIN score sc ON sc.s_id=st.s_id
LEFT JOIN course c ON c.c_id=sc.c_id
WHERE (
SELECT COUNT(1) FROM student st2
LEFT JOIN score sc2 ON sc2.s_id=st2.s_id
LEFT JOIN course c2 ON c2.c_id=sc2.c_id
WHERE sc.s_score=sc2.s_score AND c.c_id!=c2.c_id
)>1
##########################################
42、查询每门功成绩最好的前两名
##########################################
SELECT a.s_id,a.c_id,a.s_score
FROM score a
WHERE (SELECT COUNT(1) FROM score b WHERE b.c_id=a.c_id AND b.s_score>=a.s_score)<=2
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
SELECT c_id, COUNT() AS num
FROM score
GROUP BY c_id
HAVING num > 5
ORDER BY num DESC, c_id
-- 44、检索至少选修两门课程的学生学号
SELECT s_id
FROM score
GROUP BY s_id
HAVING COUNT() >=2
-- 45、查询选修了全部课程的学生信息
SELECT s.*
FROM Student s
JOIN score sc ON s.s_id = sc.s_id
GROUP BY s.s_id
HAVING COUNT() = (
SELECT COUNT() FROM course)
-- 46、查询各学生的年龄
SELECT *, YEAR(NOW())-YEAR(s_birth)
FROM student
SELECT st.*,TIMESTAMPDIFF(YEAR,st.s_birth,NOW()) FROM student st
-- 47、查询本周过生日的学生
SELECT st.* FROM student st
WHERE WEEK(NOW())=WEEK(DATE_FORMAT(st.s_birth,'%Y%m%d'))
-- 48、查询下周过生日的学生
SELECT s.* FROM student s
WHERE WEEK(NOW()) + 1 = WEEK(DATE_FORMAT(s.s_birth,'%Y%m%d'))
-- 49、查询本月过生日的学生
SELECT st.* FROM student st
WHERE MONTH(NOW())=MONTH(DATE_FORMAT(st.s_birth,'%Y%m%d'))
-- 50、查询下月过生日的学生
SELECT st.* FROM student st
WHERE MONTH(NOW()) + 1 = MONTH(st.s_birth)
SELECT st.* FROM student st
WHERE MONTH(NOW())+1=MONTH(DATE_FORMAT(st.s_birth,'%Y%m%d'))
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