From ad28d1a12442f83f8887bc7b06c719d7641857c6 Mon Sep 17 00:00:00 2001 From: Aliaksei Khatskevich Date: Wed, 6 Dec 2023 22:33:03 +0100 Subject: [PATCH] Add named collections to mysql table function docs --- .../en/sql-reference/table-functions/mysql.md | 26 ++++++++++++------- 1 file changed, 16 insertions(+), 10 deletions(-) diff --git a/docs/en/sql-reference/table-functions/mysql.md b/docs/en/sql-reference/table-functions/mysql.md index 0e5b0f54d1c..5fd9708317c 100644 --- a/docs/en/sql-reference/table-functions/mysql.md +++ b/docs/en/sql-reference/table-functions/mysql.md @@ -11,31 +11,25 @@ Allows `SELECT` and `INSERT` queries to be performed on data that is stored on a **Syntax** ``` sql -mysql('host:port', 'database', 'table', 'user', 'password'[, replace_query, 'on_duplicate_clause']) +mysql({host:port, database, table, user, password[, replace_query, on_duplicate_clause] | named_collection[, option=value [,..]]}) ``` -**Arguments** +**Parameters** - `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. +Arguments also can be passed using [named collections](/docs/en/operations/named-collections.md). In this case `host` and `port` should be specified separately. This approach is recommended for production environment. + 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. @@ -86,6 +80,18 @@ Selecting data from ClickHouse: SELECT * FROM mysql('localhost:3306', 'test', 'test', 'bayonet', '123'); ``` +Or using [named collections](/docs/en/operations/named-collections.md): + +```sql +CREATE NAMED COLLECTION creds AS + host = 'localhost', + port = 3306, + database = 'test', + user = 'bayonet', + password = '123'; +SELECT * FROM mysql(creds, table='test'); +``` + ``` text ┌─int_id─┬─float─┐ │ 1 │ 2 │