mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-25 09:02:00 +00:00
102 lines
3.2 KiB
Markdown
102 lines
3.2 KiB
Markdown
---
|
||
toc_priority: 42
|
||
toc_title: mysql
|
||
---
|
||
|
||
# mysql {#mysql}
|
||
|
||
Allows `SELECT` and `INSERT` queries to be performed on data that is stored on a remote MySQL server.
|
||
|
||
**Syntax**
|
||
|
||
``` sql
|
||
mysql('host:port', 'database', 'table', 'user', 'password'[, replace_query, 'on_duplicate_clause'])
|
||
```
|
||
|
||
**Arguments**
|
||
|
||
- `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` queries to `REPLACE INTO`. Possible values:
|
||
- `0` - The query is executed as `INSERT INTO`.
|
||
- `1` - The query is executed as `REPLACE INTO`.
|
||
|
||
- `on_duplicate_clause` — The `ON DUPLICATE KEY on_duplicate_clause` expression that is added to the `INSERT` query. Can be specified only with `replace_query = 0` (if you simultaneously pass `replace_query = 1` and `on_duplicate_clause`, ClickHouse generates an exception).
|
||
|
||
Example: `INSERT INTO t (c1,c2) VALUES ('a', 2) ON DUPLICATE KEY UPDATE c2 = c2 + 1;`
|
||
|
||
`on_duplicate_clause` here is `UPDATE c2 = c2 + 1`. See the MySQL documentation to find which `on_duplicate_clause` you can use with the `ON DUPLICATE KEY` clause.
|
||
|
||
Simple `WHERE` clauses such as `=, !=, >, >=, <, <=` are currently executed on the MySQL server.
|
||
|
||
The rest of the conditions and the `LIMIT` sampling constraint are executed in ClickHouse only after the query to MySQL finishes.
|
||
|
||
**Returned Value**
|
||
|
||
A table object with the same columns as the original MySQL table.
|
||
|
||
!!! info "Note"
|
||
In the `INSERT` query to distinguish table function `mysql(...)` from table name with column names list, you must use keywords `FUNCTION` or `TABLE FUNCTION`. See examples below.
|
||
|
||
**Examples**
|
||
|
||
Table in MySQL:
|
||
|
||
``` text
|
||
mysql> CREATE TABLE `test`.`test` (
|
||
-> `int_id` INT NOT NULL AUTO_INCREMENT,
|
||
-> `float` FLOAT NOT NULL,
|
||
-> PRIMARY KEY (`int_id`));
|
||
|
||
mysql> INSERT INTO test (`int_id`, `float`) VALUES (1,2);
|
||
|
||
mysql> SELECT * FROM test;
|
||
+--------+-------+
|
||
| int_id | float |
|
||
+--------+-------+
|
||
| 1 | 2 |
|
||
+--------+-------+
|
||
```
|
||
|
||
Selecting data from ClickHouse:
|
||
|
||
``` sql
|
||
SELECT * FROM mysql('localhost:3306', 'test', 'test', 'bayonet', '123');
|
||
```
|
||
|
||
``` text
|
||
┌─int_id─┬─float─┐
|
||
│ 1 │ 2 │
|
||
└────────┴───────┘
|
||
```
|
||
|
||
Replacing and inserting:
|
||
|
||
```sql
|
||
INSERT INTO FUNCTION mysql('localhost:3306', 'test', 'test', 'bayonet', '123', 1) (int_id, float) VALUES (1, 3);
|
||
INSERT INTO TABLE FUNCTION mysql('localhost:3306', 'test', 'test', 'bayonet', '123', 0, 'UPDATE int_id = int_id + 1') (int_id, float) VALUES (1, 4);
|
||
SELECT * FROM mysql('localhost:3306', 'test', 'test', 'bayonet', '123');
|
||
```
|
||
|
||
``` text
|
||
┌─int_id─┬─float─┐
|
||
│ 1 │ 3 │
|
||
│ 2 │ 4 │
|
||
└────────┴───────┘
|
||
```
|
||
|
||
**See Also**
|
||
|
||
- [The ‘MySQL’ table engine](../../engines/table-engines/integrations/mysql.md)
|
||
- [Using MySQL as a source of external dictionary](../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-sources.md#dicts-external_dicts_dict_sources-mysql)
|
||
|
||
[Original article](https://clickhouse.tech/docs/en/sql-reference/table_functions/mysql/) <!--hide-->
|