ClickHouse/docs/zh/sql-reference/table-functions/mysql.md

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---
machine_translated: true
machine_translated_rev: 72537a2d527c63c07aa5d2361a8829f3895cf2bd
toc_priority: 42
toc_title: mysql
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---
# mysql {#mysql}
允许 `SELECT` 要对存储在远程MySQL服务器上的数据执行的查询。
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``` sql
mysql('host:port', 'database', 'table', 'user', 'password'[, replace_query, 'on_duplicate_clause']);
```
**参数**
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- `host:port` — MySQL server address.
- `database` — Remote database name.
- `table` — Remote table name.
- `user` — MySQL user.
- `password` — User password.
- `replace_query` — Flag that converts `INSERT INTO` 查询到 `REPLACE INTO`. 如果 `replace_query=1`,查询被替换。
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- `on_duplicate_clause` — The `ON DUPLICATE KEY on_duplicate_clause` 表达式被添加到 `INSERT` 查询。
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Example: `INSERT INTO t (c1,c2) VALUES ('a', 2) ON DUPLICATE KEY UPDATE c2 = c2 + 1`, where `on_duplicate_clause` is `UPDATE c2 = c2 + 1`. See the MySQL documentation to find which `on_duplicate_clause` you can use with the `ON DUPLICATE KEY` clause.
To specify `on_duplicate_clause` you need to pass `0` to the `replace_query` parameter. If you simultaneously pass `replace_query = 1` and `on_duplicate_clause`, ClickHouse generates an exception.
简单 `WHERE` 条款如 `=, !=, >, >=, <, <=` 当前在MySQL服务器上执行。
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其余的条件和 `LIMIT` 只有在对MySQL的查询完成后才会在ClickHouse中执行采样约束。
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**返回值**
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与原始MySQL表具有相同列的table对象。
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## 用法示例 {#usage-example}
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MySQL中的表:
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``` text
mysql> CREATE TABLE `test`.`test` (
-> `int_id` INT NOT NULL AUTO_INCREMENT,
-> `int_nullable` INT NULL DEFAULT NULL,
-> `float` FLOAT NOT NULL,
-> `float_nullable` FLOAT NULL DEFAULT NULL,
-> PRIMARY KEY (`int_id`));
Query OK, 0 rows affected (0,09 sec)
mysql> insert into test (`int_id`, `float`) VALUES (1,2);
Query OK, 1 row affected (0,00 sec)
mysql> select * from test;
+------+----------+-----+----------+
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| int_id | int_nullable | float | float_nullable |
+------+----------+-----+----------+
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| 1 | NULL | 2 | NULL |
+------+----------+-----+----------+
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1 row in set (0,00 sec)
```
从ClickHouse中选择数据:
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``` sql
SELECT * FROM mysql('localhost:3306', 'test', 'test', 'bayonet', '123')
```
``` text
┌─int_id─┬─int_nullable─┬─float─┬─float_nullable─┐
│ 1 │ ᴺᵁᴸᴸ │ 2 │ ᴺᵁᴸᴸ │
└────────┴──────────────┴───────┴────────────────┘
```
## 另请参阅 {#see-also}
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- [MySQL 表引擎](../../engines/table-engines/integrations/mysql.md)
- [使用MySQL作为外部字典的来源](../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-sources.md#dicts-external_dicts_dict_sources-mysql)
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[原始文章](https://clickhouse.tech/docs/en/query_language/table_functions/mysql/) <!--hide-->