---
title: num_vals() | Tiger Data Docs
description: Get the number of values contained in a `tdigest`
---

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

Get the number of values contained in a `tdigest` aggregate. This accessor allows you to calculate a count alongside percentiles, without needing to create two separate aggregates from the same raw data.

## Samples

Count the number of integers from 0 to 100.

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

```
num_vals
-----------
    101
```

## Arguments

The syntax is:

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

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

## Returns

| Column    | Type             | Description                            |
| --------- | ---------------- | -------------------------------------- |
| num\_vals | DOUBLE PRECISION | The number of values in the `tdigest`. |