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* enbaskakova-DOCSUP-652 (#101)
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* Update docs/en/sql_reference/aggregate_functions/combinators.md
Co-Authored-By: BayoNet <da-daos@yandex.ru>
* Update docs/en/sql_reference/aggregate_functions/combinators.md
Co-Authored-By: BayoNet <da-daos@yandex.ru>
* Update docs/en/sql_reference/aggregate_functions/combinators.md
Co-Authored-By: BayoNet <da-daos@yandex.ru>
* Update docs/en/sql_reference/aggregate_functions/combinators.md
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* Update docs/en/sql_reference/aggregate_functions/combinators.md
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* "docs(orNull&orDefault): Functions 'orNull&orDefault' have been edited"
* "docs(orNull&orDefault): Functions 'orNull&orDefault' have been edited"
* "docs(orNull&orDefault): Functions 'orNull&orDefault' have been edited"
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* Revert "enbaskakova-DOCSUP-652 (#101)" (#107)
This reverts commit 639fee7610.
* CLICKHOUSEDOCS-624: Fixed links. Was 60, became 13.
* CLICKHOUSEDOCS-624: Finished fix links in Enlish version.
* CLICKHOUSEDOCS-624: Fixed RU links
Co-authored-by: elenaspb2019 <47083263+elenaspb2019@users.noreply.github.com>
Co-authored-by: elenbaskakova <elenbaskakova@yandex-team.ru>
Co-authored-by: Sergei Shtykov <bayonet@yandex-team.ru>
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| toc_folder_title | toc_priority | toc_title |
|---|---|---|
| Dictionaries | 35 | Introduction |
Dictionaries
A dictionary is a mapping (key -> attributes) that is convenient for various types of reference lists.
ClickHouse supports special functions for working with dictionaries that can be used in queries. It is easier and more efficient to use dictionaries with functions than a JOIN with reference tables.
NULL values can’t be stored in a dictionary.
ClickHouse supports:
- Built-in dictionaries with a specific set of functions.
- Plug-in (external) dictionaries with a set of functions.