> ## Documentation Index
> Fetch the complete documentation index at: https://upstash-worktree-docs-descriptions.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Overview

> Compute summary metrics like avg, sum, min, max, count, cardinality, stats, and percentiles over matched documents in Upstash Redis Search.

Metric aggregations compute summary numbers over all documents that matched your `filter`.

Use metrics when you want one value (or stats object), not grouped buckets.

### Available Operators

| Operator                             | What it computes                              |
| ------------------------------------ | --------------------------------------------- |
| [`$avg`](./avg)                      | Arithmetic mean                               |
| [`$sum`](./sum)                      | Total of values                               |
| [`$min`](./min)                      | Smallest value                                |
| [`$max`](./max)                      | Largest value                                 |
| [`$count`](./count)                  | Count of values                               |
| [`$cardinality`](./cardinality)      | Count of distinct values                      |
| [`$stats`](./stats)                  | `count`, `sum`, `min`, `max`, `avg`           |
| [`$extendedStats`](./extended-stats) | `$stats` + variance and std deviation metrics |
| [`$percentiles`](./percentiles)      | Distribution percent points                   |

### Input Format

Every metric operator takes an object with at least a `field` property:

```json theme={"system"}
{"alias_name": {"$avg": {"field": "price"}}}
{"alias_name": {"$avg": {"field": "price", "missing": 0}}}
```

The `field` value must be a string pointing to a FAST field in your schema.

### Behavior Notes

* Metric operators require a `field`.
* The field must be `FAST` in your schema.
* Metric operators do not support nested `$aggs`.
* For many metric operators, `missing` lets you provide a fallback value for documents where the field does not exist.