Cumulative computation with RavenDB queries
Consider the image on the right, where we have three charges on separate months. This is a time series, showing charges over time. We can very easily issue queries that will give us the results of how much we paid in a time period, but what if we wanted to get the cumulative value. How much have I paid so far? Here is how this should look like:
However, that is not something that we provide in RavenDB. Luckily, we do provide a very flexible query engine, so we can make it happen anyway. Here is what the query will look like:
I didn't get into time series features yet so I wonder, will that query create an index (with Sum as a stored field?) or it will be computed on-the-fly? If on-the-fly is /will be there a way to write that query in C#?
This is computed on the fly, yes. And you can probably write in C#, but it would be a PITA to do so. Easier to do that in JS.C# also doesn't support an easy way to return multiple results per document, like we are doing here.