---
title: mean() | Tiger Data Docs
description: Calculate the exact mean from values in a `tdigest`
---

Since [1.0.0](https://github.com/timescale/timescaledb-toolkit/releases/tag/1.0.0)

Calculate the exact mean of the values in a `tdigest` aggregate. Unlike percentile calculations, the mean calculation is exact. This accessor allows you to calculate the mean alongside percentiles, without needing to create two separate aggregates from the same raw data.

## Samples

Calculate the mean of the integers from 0 to 100.

```
SELECT mean(tdigest(data))
FROM generate_series(0, 100) data;
```

```
mean
------
50
```

## Arguments

The syntax is:

```
mean(
  digest TDigest
) RETURNS DOUBLE PRECISION
```

| Name   | Type    | Default | Required | Description                                      |
| ------ | ------- | ------- | -------- | ------------------------------------------------ |
| digest | TDigest | -       | ✔        | The `tdigest` aggregate to extract the mean from |

## Returns

| Column | Type             | Description                              |
| ------ | ---------------- | ---------------------------------------- |
| mean   | DOUBLE PRECISION | The mean of the values in the `tdigest`. |