ClickHouse/docs/en/query_language/functions/ext_dict_functions.md
Ivan Blinkov 0a4a5b36cc
Some WIP on documentation refactoring (#2659)
* Additional .gitignore entries

* Merge a bunch of small articles about system tables into single one

* Merge a bunch of small articles about formats into single one

* Adapt table with formats to English docs too

* Add SPb meetup link to main page

* Move Utilities out of top level of docs (the location is probably not yet final) + translate couple articles

* Merge MacOS.md into build_osx.md

* Move Data types higher in ToC

* Publish changelog on website alongside documentation

* Few fixes for en/table_engines/file.md

* Use smaller header sizes in changelogs

* Group up table engines inside ToC

* Move table engines out of top level too

* Specificy in ToC that query language is SQL based. Thats a bit excessive, but catches eye.

* Move stuff that is part of query language into respective folder

* Move table functions lower in ToC

* Lost redirects.txt update

* Do not rely on comments in yaml + fix few ru titles

* Extract major parts of queries.md into separate articles

* queries.md has been supposed to be removed

* Fix weird translation

* Fix a bunch of links

* There is only table of contents left

* "Query language" is actually part of SQL abbreviation

* Change filename in README.md too

* fix mistype
2018-07-18 13:00:53 +03:00

1.5 KiB

Functions for working with external dictionaries

For information on connecting and configuring external dictionaries, see "External dictionaries".

dictGetUInt8, dictGetUInt16, dictGetUInt32, dictGetUInt64

dictGetInt8, dictGetInt16, dictGetInt32, dictGetInt64

dictGetFloat32, dictGetFloat64

dictGetDate, dictGetDateTime

dictGetUUID

dictGetString

dictGetT('dict_name', 'attr_name', id)

  • Get the value of the attr_name attribute from the dict_name dictionary using the 'id' key.dict_name and attr_name are constant strings.idmust be UInt64. If there is no id key in the dictionary, it returns the default value specified in the dictionary description.

dictGetTOrDefault

dictGetT('dict_name', 'attr_name', id, default)

The same as the dictGetT functions, but the default value is taken from the function's last argument.

dictIsIn

dictIsIn('dict_name', child_id, ancestor_id)

  • For the 'dict_name' hierarchical dictionary, finds out whether the 'child_id' key is located inside 'ancestor_id' (or matches 'ancestor_id'). Returns UInt8.

dictGetHierarchy

dictGetHierarchy('dict_name', id)

  • For the 'dict_name' hierarchical dictionary, returns an array of dictionary keys starting from 'id' and continuing along the chain of parent elements. Returns Array(UInt64).

dictHas

dictHas('dict_name', id)

  • Check whether the dictionary has the key. Returns a UInt8 value equal to 0 if there is no key and 1 if there is a key.