常用sql语句整理：mysql

全栈程序员-站长 • 2021年10月10日下午7:00 • 未分类 • 阅读 50

## 常用sql语句整理：mysql

1. 增

– 增加一张表
“`
CREATE TABLE `table_name`(
…
)ENGINE=InnoDB DEFAULT CHARSET=utf8;
“`

– 增加记录
“`
INSERT INTO `your_table_name`(`column_name`)
VALUES
(‘your_value_one’),
(‘your_value_two’);
“`

– 增加字段
“`
ALTER TABLE `your_table_name`
ADD `your_column_name` …
AFTER `column_name`;
“`

– 增加索引
+ 主键
“`
ALTER TABLE `your_table_name`
ADD PRIMARY KEY your_index_name(your_column_name);
“`
+ 唯一索引
“`
ALTER TABLE `your_table_name`
ADD UNIQUE your_index_name(your_column_name);
“`
+ 普通索引
“`
ALTER TABLE `your_table_name`
ADD INDEX your_index_name(your_column_name);
“`
+ 全文索引
“`
ALTER TABLE `your_table_name`
ADD FULLTEXT your_index_name(your_column_name);
“`

2. 删

– 逐行删除
“`
DELETE FORM `table_name`
WHERE …;
“`

– 清空整张表
“`
TRUNCATE TABLE `your_table_name`;
“`

– 删除表
“`
DROP TABLE `your_table_name`;
“`

– 删除字段
“`
ALTER TABLE `your_table_name`
DROP `column_name`;
“`

– 删除索引
“`
ALTER TABLE `your_table_name`
DROP INDEX your_index_name(your_column_name);
“`

3. 改

– 变更数据
“`
UPDATE `table_name`
SET column_name=your_value
WHERE …;
“`

– 变更字段
“`
ALTER TABLE `your_table_name`
CHANGE `your_column_name` `your_column_name` …(变更);
“`

– 变更字段值为另一张表的某个值
“`
UPDATE `your_table_name`
AS a
JOIN `your_anther_table_name`
AS b
SET a.column = b.anther_column
WHERE a.id = b.a_id…;
“`

4. 查

– 普通查询
“`
SELECT `column_name_one`, `column_name_two`
FROM `table_name`;
“`

– 关联查询
“`
SELECT *
FROM `your_table_name`
AS a
JOIN `your_anther_table_name`
AS b
WHERE a.column_name = b.column_name…;
“`

– 合计函数条件查询：WHERE 关键字无法与合计函数一起使用
“`
SELECT aggregate_function(column_name)
FROM your_table_name
GROUP BY column_name
HAVING aggregate_function(column_name)…;
“`

– 同一个实例下跨库查询
“`
SELECT *
FROM database_name.your_table_name
AS a
JOIN another_database_name.your_another_table_name
AS b
WHERE a.column_name = b.column_name…;
“`

5. 复制一张表结构
“`
CREATE TABLE `your_table_name`
LIKE `destination_table_name`;
“`

6. 完全复制一张表：表结构+全部数据
“`
CREATE TABLE `your_table_name`
LIKE `destination_table_name`;

INSERT INTO `your_table_name`
SELECT *
FROM `destination_table_name`;
“`

—

### 附录：mysql常用命令
– 登陆： mysql -h host -u username -p
– 列出数据库：SHOW DATABESES;
– 列出表:SHOW TABLES;
– 列出表结构:DESC table_name
– 使用一个数据库：USE database_name;
– 导入：source ‘file’;
– 导出：mysqldump -h 127.0.0.1 -u root -p “database_name” “table_name” –where=”condition” > file_name.sql;
– 查看慢日志：mysqldumpslow -s [c:按记录次数排序/t:时间/l:锁定时间/r:返回的记录数] -t [n:前n条数据] -g “正则”　/path
– 新增用户： insert into `user`(`Host`, `User`, `authentication_string`) value(‘localhost’, ‘username’, password(‘pwd’))

### mysql 5.7 新增用户

“`
// 插入新用户
insert into mysql.user(Host, User, authentication_string, ssl_cipher, x509_issuer, x509_subject
value(‘localhost’, ‘username’, password(‘password’), ”, ”, ”);

// 数据库授权
grant all privileges on dbname.name.* to username@localhost identified by ‘password’;

// 刷新权限信息
FLUSH PRIVILEGES;
“`

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