elasticsearch/docs/reference/esql/processing-commands/lookup.disabled
Costin Leau bb3a24cc38
Esql/lookup join grammar (#116515) (#117107)
First PR for adding LOOKUP JOIN in ESQL.
Introduces grammar and wires the main building blocks to execute a query
 ; follow-ups are required (see #116208 for more details).

Co-authored-by: Nik Everett <nik9000@users.noreply.github.com>
(cherry picked from commit bc785f5ca1)
2024-11-20 15:02:19 +11:00

64 lines
1.6 KiB
Text

[discrete]
[[esql-lookup]]
=== `LOOKUP`
experimental::["LOOKUP is highly experimental and only available in SNAPSHOT versions."]
`LOOKUP` matches values from the input against a `table` provided in the request,
adding the other fields from the `table` to the output.
**Syntax**
[source,esql]
----
LOOKUP table ON match_field1[, match_field2, ...]
----
*Parameters*
`table`::
The name of the `table` provided in the request to match.
If the table's column names conflict with existing columns, the existing columns will be dropped.
`match_field`::
The fields in the input to match against the table.
*Examples*
// tag::examples[]
[source,console,id=esql-lookup-example]
----
POST /_query?format=txt
{
"query": """
FROM library
| SORT page_count DESC
| KEEP name, author
| LOOKUP era ON author
| LIMIT 5
""",
"tables": {
"era": {
"author": {"keyword": ["Frank Herbert", "Peter F. Hamilton", "Vernor Vinge", "Alastair Reynolds", "James S.A. Corey"]},
"era": {"keyword": [ "The New Wave", "Diamond", "Diamond", "Diamond", "Hadron"]}
}
}
}
----
// TEST[setup:library]
Which returns:
[source,text]
----
name | author | era
--------------------+-----------------+---------------
Pandora's Star |Peter F. Hamilton|Diamond
A Fire Upon the Deep|Vernor Vinge |Diamond
Dune |Frank Herbert |The New Wave
Revelation Space |Alastair Reynolds|Diamond
Leviathan Wakes |James S.A. Corey |Hadron
----
// TESTRESPONSE[s/\|/\\|/ s/\+/\\+/]
// TESTRESPONSE[non_json]
// end::examples[]