What are the three main parameters of the dimension duration type?

The three main parameters of the dimension duration type in LookML are indeed sql_start, sql_end, and intervals.

The sql_start and sql_end parameters define the start and end points of the duration dimension, allowing you to specify the timeframe for which the duration is calculated. This is crucial when you want to analyze overlapping time periods or durations defined by specific start and end dates from your dataset.

Intervals specify the granularity of the duration measurement, allowing you to categorize durations into meaningful units, such as days, weeks, or months. This flexibility lets you manipulate and analyze time series data effectively, enabling deeper insights into trends over specified durations.

The combination of these parameters provides a comprehensive way to model and work with duration dimensions in Looker, making it possible to include nuanced temporal analysis in your reports and explorations. Understanding this structure is essential to effectively using the LookML language for data modeling in Looker.