[[search-facets-terms-stats-facet]]
=== Terms Stats Facet

The `terms_stats` facet combines both the
<<search-facets-terms-facet,terms>> and
<<search-facets-statistical-facet,statistical>>
allowing to compute stats computed on a field, per term value driven by
another field. For example:

[source,js]
--------------------------------------------------
{
    "query" : {
        "match_all" : {  }
    },
    "facets" : {
        "tag_price_stats" : {
            "terms_stats" : {
                "key_field" : "tag",
                "value_field" : "price"
            }
        }
    }
}
--------------------------------------------------

The `size` parameter controls how many facet entries will be returned.
It defaults to `10`. Setting it to 0 will return all terms matching the
hits (be careful not to return too many results).

Ordering is done by setting `order`, with possible values of `term`,
`reverse_term`, `count`, `reverse_count`, `total`, `reverse_total`,
`min`, `reverse_min`, `max`, `reverse_max`, `mean`, `reverse_mean`.
Defaults to `count`.

The value computed can also be a script, using the `value_script`
instead of `value_field`, in which case the `lang` can control its
language, and `params` allow to provide custom parameters (as in other
scripted components).

Note, the terms stats can work with multi valued key fields, or multi
valued value fields, but not when both are multi valued (as ordering is
not maintained).