MySQL使用SQL语句练习题

创建数据表

CREATE TABLE user (
id int(11) NOT NULL AUTO_INCREMENT COMMENT ‘员工主键’,
username varchar(255) COLLATE utf8_bin DEFAULT NULL COMMENT ‘员工姓名’,
birthday date DEFAULT NULL COMMENT ‘员工日期’,
entry_date datetime DEFAULT NULL,
job varchar(60) CHARACTER SET utf8 DEFAULT NULL,
salary float(10,2) DEFAULT NULL,
resume text COLLATE utf8_bin,
image varchar(255) COLLATE utf8_bin DEFAULT NULL,
PRIMARY KEY (id)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin;

一、插入语句 —insert

INSERT INTO mydb.user(id, username, birthday, entry_date, job, salary, resume, image) VALUES (1, ‘李四’, ‘2020-10-11’, ‘2020-10-12 00:00:00’, ‘ccc’, 4000.00, ‘河南郑州’, NULL);
INSERT INTO mydb.user(id, username, birthday, entry_date, job, salary, resume, image) VALUES (2, ‘张三’, ‘2020-07-21’, ‘2020-07-21 15:20:29’, ‘员工’, 3000.00, ‘河南新乡’, NULL);
INSERT INTO mydb.user(id, username, birthday, entry_date, job, salary, resume, image) VALUES (3, ‘王五’, ‘2020-07-21’, ‘2020-07-21 15:31:10’, ‘员工’, 6000.00, ‘河南驻马店’, NULL);
INSERT INTO mydb.user(id, username, birthday, entry_date, job, salary, resume, image) VALUES (4, ‘sada’, ‘2020-07-21’, ‘2020-07-21 15:47:54’, ‘vv’, 453.00, ‘dsf’, NULL);

二、更新语句 —update

1、将所有员工薪水修改为5000元

UPDATE mydb.user SET salary = 5000 WHEREjob = ‘员工’;

2、将姓名为’zs’的员工薪水修改为3000元。

UPDATE mydb.user SET salary = 3000, job = ‘员工’ WHERE username=‘张三’;

3、将姓名为’ls’的员工薪水修改为4000元,job改为ccc。

UPDATE mydb.user SET salary = 4000, job = ‘ccc’ WHERE username=‘李四’;

4、将wangwu的薪水在原有基础上增加1000元。

UPDATE mydb.user SET salary = salary+1000 WHERE username=‘王五’;

#三、删除语句 —delete
#1、删除表中名称为’zs’的记录。
delete from user where username=‘张三’;

2、删除表中所有记录。

truncate table user;
#查询信息
SELECT * FROM mydb.user LIMIT 0,1000