sql.md

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 `your_table_name`
LIKE `destination_table_name`;

6. 完全复制一张表：表结构+全部数据

CREATE `your_table_name`
LIKE `destination_table_name`;

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

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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：DESC TABLES;
• 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;