66 lines
1.5 KiB
Markdown
66 lines
1.5 KiB
Markdown
### MySQL-1
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```sql
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#1.添加字段
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ALTER TABLE t_student ADD descr VARCHAR(200) DEFAULT '无';
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#2.插入记录
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INSERT INTO t_student()
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VALUES(DEFAULT, '林小莉', '女', 8, 10005,'13971555555', '身体瘦弱，训练强度需要调整');
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#3.简单查询 tj11
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SELECT c.id, c.`name`, CONCAT(YEAR(c.time),'年',MONTH(c.time),'月', DAY(c.time),'日')
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FROM t_class c;
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#4.排序、分页查询 tj12
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SELECT *
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FROM t_coach c
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ORDER BY c.salary
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LIMIT 1, 2;
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#5.模糊、多表连接查询 tj13
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SELECT co.`name`, cl.`name`, cl.period
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FROM t_coach co, t_class cl
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WHERE co.id = cl.coachId AND co.`name` LIKE '何%';
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#6.更新记录
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UPDATE t_coach c
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SET c.salary = c.salary + 200
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WHERE c.age >= 30;
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#7.多表联查+视图
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CREATE VIEW v_swim AS
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SELECT s.`name` '学员姓名', co.`name` '教练姓名', cl.`name` '班级名称'
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FROM t_student s, t_class cl, t_coach co
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WHERE s.classId = cl.id AND cl.coachId = co.id;
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#8.插入操作的触发器
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DELIMITER $$
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DROP TRIGGER IF EXISTS tri_familylog;
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CREATE TRIGGER tri_familylog
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AFTER DELETE ON t_family
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FOR EACH ROW
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BEGIN
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INSERT INTO t_log()
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VALUES(DEFAULT, OLD.fid, '删除家庭', '2024-01-01');
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END $$
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DELIMITER ;
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#9.条件查询+聚合函数 存储过程
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DELIMITER $$
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DROP PROCEDURE IF EXISTS pro_getStudentNumber;
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CREATE PROCEDURE pro_getStudentNumber(IN in_classId INT, OUT out_number INT)
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BEGIN
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SELECT COUNT(*) INTO out_number
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FROM t_student s
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WHERE s.classId = in_classId;
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END $$
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DELIMITER ;
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#测试存储过程
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CALL pro_getStudentNumber(10002, @result);
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SELECT @result;
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```
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