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update pages that refer to dictionaries
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@ -6,7 +6,7 @@ sidebar_label: Integrations
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# Table Engines for Integrations
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ClickHouse provides various means for integrating with external systems, including table engines. Like with all other table engines, the configuration is done using `CREATE TABLE` or `ALTER TABLE` queries. Then from a user perspective, the configured integration looks like a normal table, but queries to it are proxied to the external system. This transparent querying is one of the key advantages of this approach over alternative integration methods, like external dictionaries or table functions, which require to use custom query methods on each use.
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ClickHouse provides various means for integrating with external systems, including table engines. Like with all other table engines, the configuration is done using `CREATE TABLE` or `ALTER TABLE` queries. Then from a user perspective, the configured integration looks like a normal table, but queries to it are proxied to the external system. This transparent querying is one of the key advantages of this approach over alternative integration methods, like dictionaries or table functions, which require to use custom query methods on each use.
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List of supported integrations:
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@ -180,6 +180,6 @@ Default value: `300`.
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## See Also {#see-also}
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- [The mysql table function](../../../sql-reference/table-functions/mysql.md)
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- [Using MySQL as a source of external dictionary](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-sources.md#dicts-external_dicts_dict_sources-mysql)
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- [Using MySQL as a dictionary source](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-sources.md#dicts-external_dicts_dict_sources-mysql)
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[Original article](https://clickhouse.com/docs/en/engines/table-engines/integrations/mysql/) <!--hide-->
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@ -126,7 +126,7 @@ SELECT * FROM odbc_t
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## See Also {#see-also}
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- [ODBC external dictionaries](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-sources.md#dicts-external_dicts_dict_sources-odbc)
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- [ODBC dictionaries](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-sources.md#dicts-external_dicts_dict_sources-odbc)
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- [ODBC table function](../../../sql-reference/table-functions/odbc.md)
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[Original article](https://clickhouse.com/docs/en/engines/table-engines/integrations/odbc/) <!--hide-->
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@ -174,6 +174,6 @@ CREATE TABLE pg_table_schema_with_dots (a UInt32)
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**See Also**
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- [The `postgresql` table function](../../../sql-reference/table-functions/postgresql.md)
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- [Using PostgreSQL as a source of external dictionary](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-sources.md#dicts-external_dicts_dict_sources-postgresql)
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- [Using PostgreSQL as a dictionary source](../../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-sources.md#dicts-external_dicts_dict_sources-postgresql)
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[Original article](https://clickhouse.com/docs/en/engines/table-engines/integrations/postgresql/) <!--hide-->
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@ -129,7 +129,7 @@ SELECT mcc, count() FROM cell_towers GROUP BY mcc ORDER BY count() DESC LIMIT 10
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So, the top countries are: the USA, Germany, and Russia.
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You may want to create an [External Dictionary](../../sql-reference/dictionaries/external-dictionaries/external-dicts.md) in ClickHouse to decode these values.
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You may want to create a [Dictionary](../../sql-reference/dictionaries/external-dictionaries/external-dicts.md) in ClickHouse to decode these values.
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## Use case: Incorporate geo data {#use-case}
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@ -5,7 +5,7 @@ sidebar_label: Input and Output Formats
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title: Formats for Input and Output Data
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---
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ClickHouse can accept and return data in various formats. A format supported for input can be used to parse the data provided to `INSERT`s, to perform `SELECT`s from a file-backed table such as File, URL or HDFS, or to read an external dictionary. A format supported for output can be used to arrange the
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ClickHouse can accept and return data in various formats. A format supported for input can be used to parse the data provided to `INSERT`s, to perform `SELECT`s from a file-backed table such as File, URL or HDFS, or to read a dictionary. A format supported for output can be used to arrange the
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results of a `SELECT`, and to perform `INSERT`s into a file-backed table.
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The supported formats are:
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@ -130,7 +130,7 @@ SHOW TABLES FROM mydatabase;
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└────────┘
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```
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### Example of using named collections with an external dictionary with source MySQL
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### Example of using named collections with a dictionary with source MySQL
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```sql
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CREATE DICTIONARY dict (A Int64, B String)
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@ -213,7 +213,7 @@ SHOW TABLES FROM mydatabase
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└──────┘
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```
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### Example of using named collections with an external dictionary with source POSTGRESQL
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### Example of using named collections with a dictionary with source POSTGRESQL
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```sql
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CREATE DICTIONARY dict (a Int64, b String)
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@ -270,7 +270,7 @@ SELECT * FROM remote(remote1, database = default, table = test);
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└───┴───┘
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```
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### Example of using named collections with an external dictionary with source ClickHouse
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### Example of using named collections with a dictionary with source ClickHouse
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```sql
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CREATE DICTIONARY dict(a Int64, b String)
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@ -268,14 +268,14 @@ The path to the table in ZooKeeper.
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## dictionaries_config {#server_configuration_parameters-dictionaries_config}
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The path to the config file for external dictionaries.
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The path to the config file for dictionaries.
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Path:
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- Specify the absolute path or the path relative to the server config file.
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- The path can contain wildcards \* and ?.
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See also “[External dictionaries](../../sql-reference/dictionaries/external-dictionaries/external-dicts.md)”.
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See also “[Dictionaries](../../sql-reference/dictionaries/external-dictionaries/external-dicts.md)”.
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**Example**
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@ -22,7 +22,7 @@ ClickHouse generates an exception for errors with dictionaries. Examples of erro
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- The dictionary being accessed could not be loaded.
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- Error querying a `cached` dictionary.
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You can view the list of external dictionaries and their statuses in the [system.dictionaries](../../../operations/system-tables/dictionaries.md) table.
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You can view the list of dictionaries and their statuses in the [system.dictionaries](../../../operations/system-tables/dictionaries.md) table.
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:::tip
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If you are using a DICTIONARY with ClickHouse Cloud please use the DDL query option to create your dictionaries.
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@ -83,7 +83,7 @@ To respond to the query, there is a corresponding cell, and the index for the po
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- `POLYGON`. Synonym to `POLYGON_INDEX_CELL`.
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Dictionary queries are carried out using standard [functions](../../../sql-reference/functions/ext-dict-functions.md) for working with external dictionaries.
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Dictionary queries are carried out using standard [functions](../../../sql-reference/functions/ext-dict-functions.md) for working with dictionaries.
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An important difference is that here the keys will be the points for which you want to find the polygon containing them.
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**Example**
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@ -1,20 +1,20 @@
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---
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slug: /en/sql-reference/functions/ext-dict-functions
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sidebar_position: 58
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sidebar_label: External Dictionaries
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sidebar_label: Dictionaries
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---
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# Functions for Working with Dictionaries
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:::note
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For dictionaries created with [DDL queries](../../sql-reference/statements/create/dictionary.md), the `dict_name` parameter must be fully specified, like `<database>.<dict_name>`. Otherwise, the current database is used.
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:::
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# Functions for Working with External Dictionaries
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For information on connecting and configuring external dictionaries, see [External dictionaries](../../sql-reference/dictionaries/external-dictionaries/external-dicts.md).
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For information on connecting and configuring dictionaries, see [Dictionaries](../../sql-reference/dictionaries/external-dictionaries/external-dicts.md).
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## dictGet, dictGetOrDefault, dictGetOrNull
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Retrieves values from an external dictionary.
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Retrieves values from a dictionary.
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``` sql
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dictGet('dict_name', attr_names, id_expr)
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@ -52,7 +52,7 @@ Create a text file `ext-dict-test.csv` containing the following:
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The first column is `id`, the second column is `c1`.
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Configure the external dictionary:
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Configure the dictionary:
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``` xml
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<clickhouse>
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@ -112,7 +112,7 @@ Create a text file `ext-dict-mult.csv` containing the following:
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The first column is `id`, the second is `c1`, the third is `c2`.
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Configure the external dictionary:
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Configure the dictionary:
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``` xml
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<clickhouse>
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@ -185,7 +185,7 @@ INSERT INTO range_key_dictionary_source_table VALUES(2, toDate('2019-05-20'), to
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INSERT INTO range_key_dictionary_source_table VALUES(3, toDate('2019-05-20'), toDate('2019-05-20'), 'Third', 'Third');
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```
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Create the external dictionary:
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Create the dictionary:
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```sql
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CREATE DICTIONARY range_key_dictionary
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@ -226,7 +226,7 @@ Result:
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**See Also**
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- [External Dictionaries](../../sql-reference/dictionaries/external-dictionaries/external-dicts.md)
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- [Dictionaries](../../sql-reference/dictionaries/external-dictionaries/external-dicts.md)
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## dictHas
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@ -131,7 +131,7 @@ Type: `UInt32`.
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### regionToPopulation(id\[, geobase\])
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Gets the population for a region.
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The population can be recorded in files with the geobase. See the section “External dictionaries”.
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The population can be recorded in files with the geobase. See the section “Dictionaries”.
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If the population is not recorded for the region, it returns 0.
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In the geobase, the population might be recorded for child regions, but not for parent regions.
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@ -282,7 +282,7 @@ Each time a query is run with the same `JOIN`, the subquery is run again because
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In some cases, it is more efficient to use [IN](../../../sql-reference/operators/in.md) instead of `JOIN`.
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If you need a `JOIN` for joining with dimension tables (these are relatively small tables that contain dimension properties, such as names for advertising campaigns), a `JOIN` might not be very convenient due to the fact that the right table is re-accessed for every query. For such cases, there is an “external dictionaries” feature that you should use instead of `JOIN`. For more information, see the [External dictionaries](../../../sql-reference/dictionaries/external-dictionaries/external-dicts.md) section.
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If you need a `JOIN` for joining with dimension tables (these are relatively small tables that contain dimension properties, such as names for advertising campaigns), a `JOIN` might not be very convenient due to the fact that the right table is re-accessed for every query. For such cases, there is a “dictionaries” feature that you should use instead of `JOIN`. For more information, see the [Dictionaries](../../../sql-reference/dictionaries/external-dictionaries/external-dicts.md) section.
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### Memory Limitations
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## SHOW DICTIONARIES
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Displays a list of [external dictionaries](../../sql-reference/dictionaries/external-dictionaries/external-dicts.md).
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Displays a list of [Dictionaries](../../sql-reference/dictionaries/external-dictionaries/external-dicts.md).
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``` sql
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SHOW DICTIONARIES [FROM <db>] [LIKE '<pattern>'] [LIMIT <N>] [INTO OUTFILE <filename>] [FORMAT <format>]
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@ -110,5 +110,5 @@ SELECT * FROM mysql('localhost:3306', 'test', 'test', 'bayonet', '123');
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**See Also**
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- [The ‘MySQL’ table engine](../../engines/table-engines/integrations/mysql.md)
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- [Using MySQL as a source of external dictionary](../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-sources.md#dicts-external_dicts_dict_sources-mysql)
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- [Using MySQL as a dictionary source](../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-sources.md#dicts-external_dicts_dict_sources-mysql)
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@ -101,5 +101,5 @@ SELECT * FROM odbc('DSN=mysqlconn', 'test', 'test')
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## See Also
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- [ODBC external dictionaries](../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-sources.md#dicts-external_dicts_dict_sources-odbc)
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- [ODBC dictionaries](../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-sources.md#dicts-external_dicts_dict_sources-odbc)
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- [ODBC table engine](../../engines/table-engines/integrations/odbc.md).
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@ -130,6 +130,6 @@ CREATE TABLE pg_table_schema_with_dots (a UInt32)
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**See Also**
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- [The PostgreSQL table engine](../../engines/table-engines/integrations/postgresql.md)
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- [Using PostgreSQL as a source of external dictionary](../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-sources.md#dicts-external_dicts_dict_sources-postgresql)
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- [Using PostgreSQL as a dictionary source](../../sql-reference/dictionaries/external-dictionaries/external-dicts-dict-sources.md#dicts-external_dicts_dict_sources-postgresql)
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[Original article](https://clickhouse.com/docs/en/sql-reference/table-functions/postgresql/) <!--hide-->
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