What is the purpose of the sql_always_having parameter in Looker?

The sql_always_having parameter in Looker is designed to apply filters on the aggregated data after the GROUP BY operation has been performed. This means that when you define the sql_always_having clause in a measure, you are effectively adding conditions that must be met by the grouped results of the query.

Using this parameter ensures that the final results returned to the user are those that meet your specified criteria, which can be particularly useful when you want to filter based on aggregated values, such as sums or counts. For example, you might want to only show groups where the total sales exceed a certain amount. In this case, the sql_always_having condition would be applied after the aggregation is complete, allowing for more specific filtering of the output.

The other options do not describe the sql_always_having parameter accurately; they either relate to different functionalities within Looker or handle data at different stages of the querying process.