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This creates the `MV_FIRST` and `MV_LAST` functions that return the
first and last values from a multivalue field. They are noops from a
single valued field. They are quite similar to `MV_MIN` and `MV_MAX`
except they work on positional data rather than relative size. That
sounds like a large distinction, but in practice our multivalued fields
are often sorted. And when they operate on sorted arrays `MV_MIN` does
*the same* thing as `MV_FIRST`.
But there are some cases where it really does matter - say you are
`SPLIT`ing something - so `MV_FIRST(SPLIT("foo;bar;baz", ";"))` gets you
`foo` like you'd expect. No sorting needed.
Relates to #103879
32 lines
675 B
Text
32 lines
675 B
Text
[[esql-mv-functions]]
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==== {esql} multivalue functions
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++++
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<titleabbrev>Multivalue functions</titleabbrev>
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++++
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{esql} supports these multivalue functions:
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// tag::mv_list[]
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* <<esql-mv_avg>>
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* <<esql-mv_concat>>
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* <<esql-mv_count>>
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* <<esql-mv_dedupe>>
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* <<esql-mv_first>>
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* <<esql-mv_last>>
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* <<esql-mv_max>>
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* <<esql-mv_median>>
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* <<esql-mv_min>>
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* <<esql-mv_sum>>
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// end::mv_list[]
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include::mv_avg.asciidoc[]
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include::mv_concat.asciidoc[]
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include::mv_count.asciidoc[]
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include::mv_dedupe.asciidoc[]
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include::mv_first.asciidoc[]
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include::mv_last.asciidoc[]
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include::mv_max.asciidoc[]
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include::mv_median.asciidoc[]
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include::mv_min.asciidoc[]
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include::mv_sum.asciidoc[]
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