ClickHouse/docs/en/operations/table_engines/join.md
Ivan Blinkov 8623cb232c
WIP on docs/website (#3383)
* CLICKHOUSE-4063: less manual html @ index.md

* CLICKHOUSE-4063: recommend markdown="1" in README.md

* CLICKHOUSE-4003: manually purge custom.css for now

* CLICKHOUSE-4064: expand <details> before any print (including to pdf)

* CLICKHOUSE-3927: rearrange interfaces/formats.md a bit

* CLICKHOUSE-3306: add few http headers

* Remove copy-paste introduced in #3392

* Hopefully better chinese fonts #3392

* get rid of tabs @ custom.css

* Apply comments and patch from #3384

* Add jdbc.md to ToC and some translation, though it still looks badly incomplete

* minor punctuation

* Add some backlinks to official website from mirrors that just blindly take markdown sources

* Do not make fonts extra light

* find . -name '*.md' -type f | xargs -I{} perl -pi -e 's//g' {}

* find . -name '*.md' -type f | xargs -I{} perl -pi -e 's/ sql/g' {}

* Remove outdated stuff from roadmap.md

* Not so light font on front page too

* Refactor Chinese formats.md to match recent changes in other languages
2018-10-16 13:47:17 +03:00

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Join

A prepared data structure for JOIN that is always located in RAM.

Join(ANY|ALL, LEFT|INNER, k1[, k2, ...])

Engine parameters: ANY|ALL strictness; LEFT|INNER type. These parameters are set without quotes and must match the JOIN that the table will be used for. k1, k2, ... are the key columns from the USING clause that the join will be made on.

The table can't be used for GLOBAL JOINs.

You can use INSERT to add data to the table, similar to the Set engine. For ANY, data for duplicated keys will be ignored. For ALL, it will be counted. You can't perform SELECT directly from the table. The only way to retrieve data is to use it as the "right-hand" table for JOIN.

Storing data on the disk is the same as for the Set engine.

Original article