mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-12-11 17:02:25 +00:00
150 lines
4.3 KiB
Markdown
150 lines
4.3 KiB
Markdown
---
|
||
slug: /zh/engines/database-engines/mysql
|
||
sidebar_position: 30
|
||
sidebar_label: MySQL
|
||
---
|
||
|
||
# MySQL {#mysql}
|
||
|
||
MySQL引擎用于将远程的MySQL服务器中的表映射到ClickHouse中，并允许您对表进行`INSERT`和`SELECT`查询，以方便您在ClickHouse与MySQL之间进行数据交换
|
||
|
||
`MySQL`数据库引擎会将对其的查询转换为MySQL语法并发送到MySQL服务器中，因此您可以执行诸如`SHOW TABLES`或`SHOW CREATE TABLE`之类的操作。
|
||
|
||
但您无法对其执行以下操作：
|
||
|
||
- `RENAME`
|
||
- `CREATE TABLE`
|
||
- `ALTER`
|
||
|
||
## 创建数据库 {#creating-a-database}
|
||
|
||
``` sql
|
||
CREATE DATABASE [IF NOT EXISTS] db_name [ON CLUSTER cluster]
|
||
ENGINE = MySQL('host:port', ['database' | database], 'user', 'password')
|
||
```
|
||
|
||
**引擎参数**
|
||
|
||
- `host:port` — MySQL服务地址
|
||
- `database` — MySQL数据库名称
|
||
- `user` — MySQL用户名
|
||
- `password` — MySQL用户密码
|
||
|
||
## 支持的数据类型 {#data_types-support}
|
||
|
||
| MySQL | ClickHouse |
|
||
|----------------------------------|--------------------------------------------------------------|
|
||
| UNSIGNED TINYINT | [UInt8](../../sql-reference/data-types/int-uint.md) |
|
||
| TINYINT | [Int8](../../sql-reference/data-types/int-uint.md) |
|
||
| UNSIGNED SMALLINT | [UInt16](../../sql-reference/data-types/int-uint.md) |
|
||
| SMALLINT | [Int16](../../sql-reference/data-types/int-uint.md) |
|
||
| UNSIGNED INT, UNSIGNED MEDIUMINT | [UInt32](../../sql-reference/data-types/int-uint.md) |
|
||
| INT, MEDIUMINT | [Int32](../../sql-reference/data-types/int-uint.md) |
|
||
| UNSIGNED BIGINT | [UInt64](../../sql-reference/data-types/int-uint.md) |
|
||
| BIGINT | [Int64](../../sql-reference/data-types/int-uint.md) |
|
||
| FLOAT | [Float32](../../sql-reference/data-types/float.md) |
|
||
| DOUBLE | [Float64](../../sql-reference/data-types/float.md) |
|
||
| DATE | [Date](../../sql-reference/data-types/date.md) |
|
||
| DATETIME, TIMESTAMP | [DateTime](../../sql-reference/data-types/datetime.md) |
|
||
| BINARY | [FixedString](../../sql-reference/data-types/fixedstring.md) |
|
||
|
||
其他的MySQL数据类型将全部都转换为[String](../../sql-reference/data-types/string.md).
|
||
|
||
[Nullable](../../sql-reference/data-types/nullable.md)已经支持
|
||
|
||
## 全局变量支持 {#global-variables-support}
|
||
|
||
为了更好地兼容，您可以在SQL样式中设置全局变量，如`@@identifier`.
|
||
|
||
支持这些变量：
|
||
- `version`
|
||
- `max_allowed_packet`
|
||
|
||
!!! warning "警告"
|
||
到目前为止，这些变量是存根，并且不对应任何内容。
|
||
|
||
示例:
|
||
|
||
``` sql
|
||
SELECT @@version;
|
||
```
|
||
|
||
## 使用示例 {#examples-of-use}
|
||
|
||
MySQL操作:
|
||
|
||
``` text
|
||
mysql> USE test;
|
||
Database changed
|
||
|
||
mysql> CREATE TABLE `mysql_table` (
|
||
-> `int_id` INT NOT NULL AUTO_INCREMENT,
|
||
-> `float` FLOAT NOT NULL,
|
||
-> PRIMARY KEY (`int_id`));
|
||
Query OK, 0 rows affected (0,09 sec)
|
||
|
||
mysql> insert into mysql_table (`int_id`, `float`) VALUES (1,2);
|
||
Query OK, 1 row affected (0,00 sec)
|
||
|
||
mysql> select * from mysql_table;
|
||
+------+-----+
|
||
| int_id | value |
|
||
+------+-----+
|
||
| 1 | 2 |
|
||
+------+-----+
|
||
1 row in set (0,00 sec)
|
||
```
|
||
|
||
ClickHouse中的数据库，与MySQL服务器交换数据:
|
||
|
||
``` sql
|
||
CREATE DATABASE mysql_db ENGINE = MySQL('localhost:3306', 'test', 'my_user', 'user_password')
|
||
```
|
||
|
||
``` sql
|
||
SHOW DATABASES
|
||
```
|
||
|
||
``` text
|
||
┌─name─────┐
|
||
│ default │
|
||
│ mysql_db │
|
||
│ system │
|
||
└──────────┘
|
||
```
|
||
|
||
``` sql
|
||
SHOW TABLES FROM mysql_db
|
||
```
|
||
|
||
``` text
|
||
┌─name─────────┐
|
||
│ mysql_table │
|
||
└──────────────┘
|
||
```
|
||
|
||
``` sql
|
||
SELECT * FROM mysql_db.mysql_table
|
||
```
|
||
|
||
``` text
|
||
┌─int_id─┬─value─┐
|
||
│ 1 │ 2 │
|
||
└────────┴───────┘
|
||
```
|
||
|
||
``` sql
|
||
INSERT INTO mysql_db.mysql_table VALUES (3,4)
|
||
```
|
||
|
||
``` sql
|
||
SELECT * FROM mysql_db.mysql_table
|
||
```
|
||
|
||
``` text
|
||
┌─int_id─┬─value─┐
|
||
│ 1 │ 2 │
|
||
│ 3 │ 4 │
|
||
└────────┴───────┘
|
||
```
|