github-mirrors/elasticsearch
1
0
Fork 0
mirror of https://github.com/elastic/elasticsearch.git synced 2025-06-29 18:03:32 -04:00
Code Issues Projects Releases Packages Wiki Activity
elasticsearch/docs/reference/query-languages/joining-queries.md
Colleen McGinnis b7e3a1e14b
[docs] Migrate docs from AsciiDoc to Markdown (#123507) 
* delete asciidoc files

* add migrated files

* fix errors

* Disable docs tests

* Clarify release notes page titles

* Revert "Clarify release notes page titles"

This reverts commit 8be688648d.

* Comment out edternal URI images

* Clean up query languages landing pages, link to conceptual docs

* Add .md to url

* Fixes inference processor nesting.

---------

Co-authored-by: Liam Thompson <32779855+leemthompo@users.noreply.github.com>
Co-authored-by: Liam Thompson <leemthompo@gmail.com>
Co-authored-by: Martijn Laarman <Mpdreamz@gmail.com>
Co-authored-by: István Zoltán Szabó <szabosteve@gmail.com>
2025-02-27 17:56:14 +01:00

1.6 KiB
Raw Blame History

mapped_pages
https://www.elastic.co/guide/en/elasticsearch/reference/current/joining-queries.html

Joining queries [joining-queries]

Performing full SQL-style joins in a distributed system like Elasticsearch is prohibitively expensive. Instead, Elasticsearch offers two forms of join which are designed to scale horizontally.

nested query
Documents may contain fields of type nested. These fields are used to index arrays of objects, where each object can be queried (with the nested query) as an independent document.
has_child and has_parent queries
A join field relationship can exist between documents within a single index. The has_child query returns parent documents whose child documents match the specified query, while the has_parent query returns child documents whose parent document matches the specified query.

Also see the terms-lookup mechanism in the terms query, which allows you to build a terms query from values contained in another document.

Notes [joining-queries-notes]

Allow expensive queries [_allow_expensive_queries_2]

Joining queries will not be executed if search.allow_expensive_queries is set to false.