diff --git a/docs/reference/query-languages/esql/esql-lookup-join.md b/docs/reference/query-languages/esql/esql-lookup-join.md index 6f358161b02ae..38e5101856fa1 100644 --- a/docs/reference/query-languages/esql/esql-lookup-join.md +++ b/docs/reference/query-languages/esql/esql-lookup-join.md @@ -1,7 +1,7 @@ --- navigation_title: "Correlate data with LOOKUP JOIN" mapped_pages: - - https://www.elastic.co/guide/en/elasticsearch/reference/current/esql-enrich-data.html + - https://www.elastic.co/guide/en/elasticsearch/reference/8.18/_lookup_join.html --- # LOOKUP JOIN [esql-lookup-join-reference] @@ -35,7 +35,7 @@ The `LOOKUP JOIN` command adds new columns to a table, with data from {{es}} ind ::: `` -: The name of the lookup index. This must be a specific index name - wildcards, aliases, and remote cluster references are not supported. +: The name of the lookup index. This must be a specific index name - wildcards, aliases, and remote cluster references are not supported. Indices used for lookups must be configured with the [`lookup` index mode](/reference/elasticsearch/index-settings/index-modules.md#index-mode-setting). `` : The field to join on. This field must exist in both your current query results and in the lookup index. If the field contains multi-valued entries, those entries will not match anything (the added fields will contain `null` for those rows). @@ -107,6 +107,7 @@ FROM employees To use `LOOKUP JOIN`, the following requirements must be met: +* Indices used for lookups must be configured with the [`lookup` index mode](/reference/elasticsearch/index-settings/index-modules.md#index-mode-setting) * **Compatible data types**: The join key and join field in the lookup index must have compatible data types. This means: * The data types must either be identical or be internally represented as the same type in {{esql}} * Numeric types follow these compatibility rules: @@ -122,7 +123,7 @@ For a complete list of supported data types and their internal representations, The following are the current limitations with `LOOKUP JOIN` -* Indices in [lookup](/reference/elasticsearch/index-settings/index-modules.md#index-mode-setting) mode are always single-sharded. +* Indices in [`lookup` mode](/reference/elasticsearch/index-settings/index-modules.md#index-mode-setting) are always single-sharded. * Cross cluster search is unsupported initially. Both source and lookup indices must be local. * Currently, only matching on equality is supported. * `LOOKUP JOIN` can only use a single match field and a single index. Wildcards, aliases, datemath, and datastreams are not supported.