> ## 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.

# Time series utilities overview

> Functions for time bucketing, ordered selection, and time-based calculations

Time series utilities provide essential functions for working with time-series data, including bucketing data by time
intervals, selecting values based on temporal ordering, and performing time-based calculations.

## Samples

### Time bucketing

Bucket temperature readings into 5-minute intervals and calculate the average:

```sql theme={"dark"}
SELECT time_bucket('5 minutes', time) AS five_min, avg(temperature)
FROM readings
GROUP BY five_min
ORDER BY five_min DESC;
```

### Ordered selection

Get the first and last temperature values for each device in 1-hour buckets:

```sql theme={"dark"}
SELECT
  device_id,
  time_bucket('1 hour', time) AS hour,
  first(temperature, time) AS first_temp,
  last(temperature, time) AS last_temp
FROM readings
GROUP BY device_id, hour
ORDER BY hour DESC;
```

### Month normalization

Normalize monthly sales metrics to account for varying month lengths:

```sql theme={"dark"}
SELECT
  time_bucket('1 month', sale_date) AS month,
  SUM(amount) AS total_sales,
  month_normalize(SUM(amount), time_bucket('1 month', sale_date)) AS normalized_sales
FROM sales
GROUP BY month
ORDER BY month;
```

## Available functions

### Time bucketing

* [`time_bucket()`][time_bucket]: bucket rows by time interval to calculate aggregates
* [`time_bucket_ng()`][time_bucket_ng]: next generation time bucketing with additional features

### Ordered selection

* [`first()`][first]: get the first value in one column when rows are ordered by another column
* [`last()`][last]: get the last value in one column when rows are ordered by another column

### Time utilities

* [`days_in_month()`][days_in_month]: calculate the number of days in a month given a timestamp
* [`month_normalize()`][month_normalize]: normalize a monthly metric based on the number of days in the month

[days_in_month]: /api-reference/timescaledb/hyperfunctions/time-series-utilities/days_in_month

[first]: /api-reference/timescaledb/hyperfunctions/time-series-utilities/first

[last]: /api-reference/timescaledb/hyperfunctions/time-series-utilities/last

[month_normalize]: /api-reference/timescaledb/hyperfunctions/time-series-utilities/month_normalize

[time_bucket]: /api-reference/timescaledb/hyperfunctions/time-series-utilities/time_bucket

[time_bucket_ng]: /api-reference/timescaledb/hyperfunctions/legacy/time_bucket_ng