MySql入坑之insert、update

一、创建表

CREATE TABLE IF NOT EXISTS tasks (
    task_id INT(11) AUTO_INCREMENT,
    subject VARCHAR(45) DEFAULT NULL,
    start_date DATE DEFAULT NULL,
    end_date DATE DEFAULT NULL,
    description VARCHAR(200) DEFAULT NULL,
    PRIMARY KEY (task_id)
)ENGINE=InnoDB DEFAULT CHARSET=utf8;

二、标题简单的MySQL insert 语句

查询：
SELECT * FROM tasks;

插入：

INSERT INTO tasks(subject,start_date,end_date,description)--输入全部的字段名
VALUES ('任务-1','2017-01-01','2017-01-02','Description 1'),
       ('任务-2','2017-01-01','2017-01-02','Description 2'),
       ('任务-3','2017-01-01','2017-01-02','Description 3');

查询：

具备select的insert语句

代码样式

INSERT INTO table1
SELECT c1,c2,FROM table2;

INSERT和ON DUPLICATE KEY UPDATE

主键task_id列已经有一个值为4的行，如果插入以下，将违法primary KEY约束

INSERT INTO tasks(task_id,subject,start_date,end_date,description)
VALUES (4,'Test ON DUPLICATE KEY UPDATE','2017-01-01','2017-01-02','Next Priority');

报错：

使用以下的语句，可以实现task_id更新

INSERT INTO tasks(task_id,subject,start_date,end_date,description)
VALUES (5,'Test ON DUPLICATE KEY UPDATE','2017-01-01','2017-01-02','Next Priority')
ON DUPLICATE KEY UPDATE 
   task_id = task_id + 3, 
   subject = 'Test ON DUPLICATE KEY UPDATE';

等效于

UPDATE tasks 
SET 
    task_id = task_id + 1,
    subject = 'Test ON DUPLICATE KEY UPDATE'
WHERE
    task_id = 7;

update语句

首先查询原来的数据：

SELECT 
	lastName,firstName,email,employeeNumber
FROM 
	employees
WHERE
	employeeNumber=1056;

然后，使用UPDATE语句将Mary的电子邮件更新为新的电子邮件：[email protected]，如下查询所示：

UPDATE
	employees
SET
	email='[email protected]'
WHERE
	employeeNumber=1056;

最后，查询更新后的数据是否生效

SELECT
	lastName,firstName,email
FROM
	employees
WHERE
  employeeNumber=1056;

如果想update多列

UPDATE
	employees
SET
	email='[email protected]'
	lastName = 'NIKO'
WHERE
	employeeNumber=1056;

常用快捷键

执行选中代码：CTRL+SHIFT+R
执行窗口代码：CTRL+R