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elasticsearch/docs/reference/esql/functions/layout/mv_append.asciidoc

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ES|QL: add MV_APPEND function (#107001) Adding `MV_APPEND(value1, value2)` function, that appends two values creating a single multi-value. If one or both the inputs are multi-values, the result is the concatenation of all the values, eg. ``` MV_APPEND([a, b], [c, d]) -> [a, b, c, d] ``` ~I think for this specific case it makes sense to consider `null` values as empty arrays, so that~ ~MV_APPEND(value, null) -> value~ ~It is pretty uncommon for ESQL (all the other functions, apart from `COALESCE`, short-circuit to `null` when one of the values is null), so let's discuss this behavior.~ [EDIT] considering the feedback from Andrei, I changed this logic and made it consistent with the other functions: now if one of the parameters is null, the function returns null
2024-06-05 01:42:29 +08:00
// This is generated by ESQL's AbstractFunctionTestCase. Do no edit it. See ../README.md for how to regenerate it.
[discrete]
[[esql-mv_append]]
=== `MV_APPEND`
*Syntax*
[.text-center]
image::esql/functions/signature/mv_append.svg[Embedded,opts=inline]
include::../parameters/mv_append.asciidoc[]
include::../description/mv_append.asciidoc[]
include::../types/mv_append.asciidoc[]