elasticsearch/docs/reference/esql/functions/mv_join.asciidoc

[[esql-mv_join]]
=== `MV_JOIN`
Converts a multivalued string field into a single valued field containing the
concatenation of all values separated by a delimiter:

[source,esql]
----
include::{esql-specs}/string.csv-spec[tag=mv_join]
----

Returns:

[%header,format=dsv,separator=|]
|===
include::{esql-specs}/string.csv-spec[tag=mv_join-result]
|===

If you want to join non-string fields call <<esql-to_string>> on them first:
[source,esql]
----
include::{esql-specs}/ints.csv-spec[tag=mv_join]
----

Returns:

[%header,format=dsv,separator=|]
|===
include::{esql-specs}/ints.csv-spec[tag=mv_join-result]
|===