How Can I Group Time Series Data into Custom Segments Using MySQL?

Grouping Time Series Data into Segments

When working with time series data sampled at regular intervals, it often becomes necessary to aggregate data over specific time segments. This empowers data analysts and engineers to gain insights from data trends and patterns in a more meaningful way.

For example, consider a table that collects samples every two seconds. To analyze the variations in count values over a longer time period, you might want to group the samples into 10 or 30-second windows. By summing or averaging the count values within each segment, you can observe patterns that might be obscured when viewing individual time points.

MySQL Query for Segmentation

To achieve this data segmentation in MySQL, you can utilize the GROUP BY clause along with arithmetic operations on the time_stamp column. By dividing the UNIX timestamp of each sample by a desired interval, you can group the samples into segments based on their time difference.

Consider the following query to group samples into 30-second segments:

GROUP BY UNIX_TIMESTAMP(time_stamp) DIV 30

This query will create groups for each 30-second interval within the time range of your data.

Customizing Segment Boundaries

The interval boundaries can be further customized using the r expression within the GROUP BY clause. By adding a positive integer value r to the UNIX timestamp before dividing, you can shift the segment boundaries.

For instance, to create 20-second segments starting at hh:mm:05 and ending at hh:mm 1:05:

GROUP BY (UNIX_TIMESTAMP(time_stamp) + 5) DIV 30

This query will group samples into 20-second segments with the first segment starting at hh:mm:05 and the last ending at hh:mm 1:05.

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