9.2 KiB
9.2 KiB
第一套
#1 插入记录
/*
主键自增字段:DEFAULT
设置成空值:NULL
*/
INSERT INTO t_employee()
VALUES('e0013', '刘红', '女', 22, '实习生', 'd0002', NULL);
#2.修改表结构
/*
修改表中字段的数据类型
ALTER TABLE 表名 MODIFY 字段名 数据类型 [约束];
*/
ALTER TABLE t_employee MODIFY sex ENUM('男', '女');
#3 创建外键
/*
学生表(学号、姓名、班级编号)
班级表(班级编号、班级名称)
外键表：学生表 主键表：班级表
ALTER TABLE 学生表 ADD CONSTRAINT fk_st FOREIGN KEY(班级编号) REFERENCES 班级表(班级编号);
FOREIGN KEY(字段) 外键表中的字段
REFERENCES 表名(字段) 字段是表中的主键
*/
ALTER TABLE 表名 ADD CONSTRAINT 外键名 FOREIGN KEY(字段名) REFERENCES 表名(主键字段名);
ALTER TABLE t_employee ADD CONSTRAINT fK_did FOREIGN KEY(did) REFERENCES t_department(did);
#4 排序、分页查询 tj11
/*
基础查询
SELECT 字段
FROM 表
ORDER BY 需要排序的字段 ASC/DESC(升序/降序)
LIMIT 起始位置,个数;
*/
#查询出员工的所有信息
SELECT *
FROM t_employee;
#在基础查询之上对年龄进行降序排序
SELECT *
FROM t_employee
ORDER BY age DESC;
#在排序的基础之上，进行分页
SELECT *
FROM t_employee
ORDER BY age DESC
LIMIT 5, 8;#第0个代表第一个 第六个使用的位置是5
#5条件查询 tj12
/*
SELECT 字段
FROM 表
WHERE 条件;
*/
SELECT *
FROM t_salary
WHERE money >= 5000 AND money <= 8000;
#6 tj13 分组查询
SELECT eid, MAX(money)
FROM t_salary
GROUP BY eid;
#7 tj14 多表联查+条件过滤
SELECT d.dname, e.ename
FROM t_employee e, t_department d
WHERE e.did = d.did AND e.position = '经理';
#8
CREATE VIEW v_hrm AS
SELECT d.dname, e.ename, s.money, s.stime
FROM t_employee e, t_department d, t_salary s
WHERE e.did = d.did AND e.eid = s.eid
ORDER BY s.stime DESC;
#9 触发器
DELIMITER $$
DROP TRIGGER IF EXISTS tri_updateGroup;
CREATE TRIGGER tri_updateGroup
BEFORE UPDATE ON t_employee
FOR EACH ROW
BEGIN
IF NEW.age != OLD.age THEN
IF NEW.age<30 THEN
SET NEW.groups = '青年';
ELSEIF NEW.age<50 THEN
SET NEW.groups = '中年';
ELSE
SET NEW.groups = '老年';
END IF;
END IF;
END $$
DELIMITER ;
#10 存储过程
DELIMITER $$ #改变代码结束符
DROP PROCEDURE IF EXISTS pro_GetTopSalary;#创建存储过程之前先删除
#设置存储过程名，传入传出参数名和数据类型
CREATE PROCEDURE pro_GetTopSalary(IN in_did CHAR(10), OUT out_ename VARCHAR(30))
BEGIN
#连接查询+排序+分页
SELECT e.ename INTO out_ename
FROM t_employee e, t_salary s
WHERE e.eid = s.eid AND e.did = in_did
ORDER BY s.money DESC
LIMIT 1;
END $$
DELIMITER ;
#调用存储过程 传入用户变量接收传出数据并使用打印出来
CALL pro_GetTopSalary('d0001', @result);
SELECT @result;
第二套
#1 创建表
CREATE TABLE t_booking(
bid CHAR(10) PRIMARY KEY,
rid CHAR(10) NOT NULL,
customerName VARCHAR(50),
tel VARCHAR(30),
btime DATE
);
#2 插入记录
INSERT INTO t_booking()
VALUES('b0001', 'r0002', '诸葛亮', '1821234567', '2023-10-01');
#3 添加字段
ALTER TABLE t_hotel ADD introduce VARCHAR(255);
#4 更新记录
UPDATE t_room r
SET r.price = 500
WHERE r.rid = 'r0003';
#5 tj11
SELECT *
FROM t_hotel h
WHERE h.`level` IN ('二星', '三星');
#6 tj12
SELECT h.hid, ROUND(AVG(r.price), 2)
FROM t_hotel h, t_room r
WHERE h.hid = r.hid
GROUP BY h.hid;
#7 子查询 + 视图
CREATE VIEW v_hotel AS
SELECT h.hname, r.rname, r.price
FROM t_hotel h, t_room r
WHERE h.hid = r.hid AND r.price =(
SELECT MAX(price)
FROM t_room
WHERE hid = h.hid
);
#8 触发器
DELIMITER $$
DROP TRIGGER IF EXISTS tri_updateIntroduce;
CREATE TRIGGER tri_updateIntroduce
BEFORE UPDATE ON t_hotel
FOR EACH ROW
BEGIN
IF NEW.`level` = '一星' OR NEW.`level` = '二星' THEN
SET NEW.introduce = '实用';
ELSEIF NEW.`level` = '三星' OR NEW.`level` = '四星' THEN
SET NEW.introduce = '豪华';
ELSEIF NEW.`level` = '五星' THEN
SET NEW.introduce = '奢华';
END IF;
END $$
DELIMITER ;
#9 存储过程
DELIMITER $$
DROP PROCEDURE IF EXISTS pro_GetLowPrice;
CREATE PROCEDURE pro_GetLowPrice(IN in_rname VARCHAR(30), OUT out_hname VARCHAR(30))
BEGIN
SELECT h.hname INTO out_hname
FROM t_hotel h, t_room r
WHERE h.hid = r.hid AND r.rname = in_rname
ORDER BY r.price
LIMIT 1;
END $$
DELIMITER ;
CALL pro_GetLowPrice('标准间', @result);
SELECT @result;
第三套
#1
CREATE TABLE tb_order(
oid INT PRIMARY KEY AUTO_INCREMENT COMMENT '订单ID',
odate DATETIME NOT NULL COMMENT '下单日期',
quantity INT NOT NULL DEFAULT 1 COMMENT '下单数量'
);
#2
ALTER TABLE tb_books MODIFY price DECIMAL(10, 2);
#3
ALTER TABLE tb_book_authors ADD CONSTRAINT tB_ibfk_1 FOREIGN KEY(book_id) REFERENCES tb_books(book_id);
ALTER TABLE tb_book_authors ADD CONSTRAINT tB_ibfk_2 FOREIGN KEY(author_id) REFERENCES tb_authors(author_id);
#4
ALTER TABLE tb_authors ADD avatar MEDIUMBLOB;
#5
#使用查询和LOAD_FILE函数 导入指定路径的图片
SELECT LOAD_FILE('C:/TTLXExam/20501071168/MYSQLDB/3/jinyong.jpg');
UPDATE tb_authors a
SET a.avatar = LOAD_FILE('C:/TTLXExam/20501071168/MYSQLDB/3/jinyong.jpg')
WHERE a.author_name = '金庸';
#6
#INSTR(主串, 子串) 判断子串在主串中的位置并返回
#SUBSTR(字符串, 起始位置) 从起始位置开始截取字符串
SELECT SUBSTR(b.note,INSTR(b.note,'-')+2)
FROM tb_books b;
UPDATE tb_books b
SET b.note = SUBSTR(b.note,INSTR(b.note,'-')+2);
#7 tj11 多表连接+条件+排序
SELECT b.book_id, b.title, a.author_id, a.author_name, b.publication_date
FROM tb_books b, tb_authors a
WHERE b.note = a.author_name AND YEAR(b.publication_date) BETWEEN 1980 AND 2010
ORDER BY b.publication_date DESC;
#8 tj12 多表连接+分组+分组后条件
SELECT a.author_id, a.author_name, COUNT(*)
FROM tb_books b, tb_authors a
WHERE b.note = a.author_name
GROUP BY a.author_id
HAVING COUNT(*) > 1;
#9 视图
CREATE VIEW v_book AS
SELECT b.genre, a.author_name, COUNT(*) c
FROM tb_books b, tb_authors a
WHERE b.note = a.author_name
GROUP BY b.genre, a.author_id #按照图书类别和作者名称进行分组
HAVING COUNT(*) = ( #子查询用来统计这个类别中 数量最多的作者的图书数量
SELECT COUNT(*)
FROM tb_books
WHERE b.genre = genre
GROUP BY note
ORDER BY COUNT(*) DESC
LIMIT 1
);
#10 触发器
DELIMITER $$
DROP TRIGGER IF EXISTS tri_updateCentury;
CREATE TRIGGER tri_updateCentury
BEFORE UPDATE ON tb_books
FOR EACH ROW
BEGIN
#方式一
/*
计算出世纪数+字符串拼接
IF NEW.publication_date <> OLD.publication_date THEN
SET NEW.century = CONCAT(FLOOR(YEAR(NEW.publication_date)/100) + 1, '世纪');
END IF;
*/
#方式二 使用多分支IF
IF NEW.publication_date <> OLD.publication_date THEN
IF YEAR(NEW.publication_date) BETWEEN 1800 AND 1899 THEN
SET NEW.century = '19世纪';
ELSEIF YEAR(NEW.publication_date) BETWEEN 1900 AND 1999 THEN
SET NEW.century = '20世纪';
ELSEIF YEAR(NEW.publication_date) BETWEEN 2000 AND 2099 THEN
SET NEW.century = '21世纪';
END IF;
END IF;
END $$
DELIMITER ;
SELECT CONCAT(FLOOR(YEAR(publication_date)/100) + 1, '世纪')
FROM tb_books;
#11 存储过程
DELIMITER $$
DROP PROCEDURE IF EXISTS pro_GetTopFictionPrice;
CREATE PROCEDURE pro_GetTopFictionPrice(IN in_genre VARCHAR(255), OUT out_title VARCHAR(255))
BEGIN
SELECT b.title INTO out_title
FROM tb_books b
WHERE b.genre = in_genre AND YEAR(b.publication_date) BETWEEN 2000 AND 2099
ORDER BY b.price DESC
LIMIT 1;
END $$
DELIMITER ;
第四套
#1
ALTER TABLE tb_students MODIFY gender ENUM('男', '女', '未知');
#2
ALTER TABLE tb_scores MODIFY score FLOAT(7, 2);
#3
CREATE TABLE tb_scores_bak1 AS
SELECT *
FROM tb_scores;
#4
UPDATE test1 t1, (
SELECT tname, CONCAT(tname,'@',COUNT(*)) str
FROM test1
GROUP BY tname
HAVING COUNT(*) IN (3, 4)
)t2
SET t1.tname = t2.str
WHERE t1.tname = t2.tname;
#5
SELECT *
FROM tb_courses c
ORDER BY c.cid+0
LIMIT 4, 11;
#6
SELECT s.stuname, TIMESTAMPDIFF(YEAR,s.birthday,'2023-12-01')
FROM tb_students s
WHERE TIMESTAMPDIFF(YEAR,s.birthday,'2023-12-01') BETWEEN 30 AND 40;
#7
SELECT st.stuname, st.gender, st.birthday, c.cname, sc.score,
IF(sc.score >= 90, '优秀',
IF(sc.score >= 80, '良好',
IF(sc.score >= 70, '中等',
IF(sc.score >= 60, '及格', '不及格'))))
FROM tb_students st, tb_scores sc, tb_courses c
WHERE st.stuid = sc.student_id AND sc.course_id = c.cid
ORDER BY sc.score DESC;
#8
CREATE VIEW v_scores AS
SELECT c.cname, CEIL(AVG(sc.score)), MAX(sc.score), MIN(sc.score)
FROM tb_students st, tb_scores sc, tb_courses c
WHERE st.stuid = sc.student_id AND sc.course_id = c.cid
GROUP BY c.cid;
#9
DELIMITER $$
CREATE TRIGGER tri_updateAgeGroup
BEFORE UPDATE ON tb_students
FOR EACH ROW
BEGIN
IF YEAR(NEW.birthday) BETWEEN 2004 AND 2024 THEN
SET NEW.age_group = '青年';
ELSEIF YEAR(NEW.birthday) BETWEEN 1984 AND 2003 THEN
SET NEW.age_group = '中年';
ELSEIF YEAR(NEW.birthday) < 1984 THEN
SET NEW.age_group = '老年';
END IF;
END $$
DELIMITER ;
#10
DELIMITER $$
DROP PROCEDURE IF EXISTS pro_GetTopStudent;
CREATE PROCEDURE pro_GetTopStudent(IN in_cid CHAR(11), OUT out_stuname VARCHAR(50))
BEGIN
SELECT st.stuname INTO out_stuname
FROM tb_students st, tb_scores sc
WHERE st.stuid = sc.student_id AND sc.course_id = in_cid
ORDER BY sc.score DESC
LIMIT 1;
END $$
DELIMITER ;
CALL pro_GetTopStudent(1, @result);
SELECT @result;