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

# num_changes()

> Get the number of times a gauge changed from a gauge aggregate

<Icon icon="flask" /> Early access <Icon icon="tag" iconType="duotone" /> Since [1.6.0][toolkit-1.6.0]

Get the number of times the gauge changed during the period summarized by the gauge aggregate.

## Samples

Get the number of times the gauge changed over each 15-minute interval.

```sql theme={"dark"}
SELECT
    id,
    bucket,
    num_changes(summary)
FROM (
    SELECT
        id,
        time_bucket('15 min'::interval, ts) AS bucket,
        gauge_agg(ts, val) AS summary
    FROM foo
    GROUP BY id, time_bucket('15 min'::interval, ts)
) t
```

## Arguments

The syntax is:

```sql theme={"dark"}
num_changes(
    summary GaugeSummary
) RETURNS BIGINT
```

| Name      | Type           | Default | Required | Description                                            |
| --------- | -------------- | ------- | -------- | ------------------------------------------------------ |
| `summary` | `GaugeSummary` | -       | ✔        | A gauge summary created using [`gauge_agg`][gauge-agg] |

## Returns

| Column       | Type   | Description                           |
| ------------ | ------ | ------------------------------------- |
| num\_changes | BIGINT | The number of times the gauge changed |

[gauge-agg]: /api-reference/timescaledb-toolkit/counters-and-gauges/gauge_agg/gauge_agg

[toolkit-1.6.0]: https://github.com/timescale/timescaledb-toolkit/releases/tag/1.6.0