![]() ![]() Using the "Math" method is a bit easier to tune, especially if you want to adjust time periods for different timezones in aggregation output where you can similarly numerically adjust by adding/subtracting the numeric difference from UTC. Or similar distribution depending on the current date when the listing is run, and of course the 15 day intervals will be consistent since the epoch date. Getting a little fancier, you can use: db.col.aggregate([ This all can be done using the mongo shell. We can group-by the data according to dates. Storing data along with dates is useful in various ways. There is also a specific article on date aggregation operators. We can store dates in MongoDB using date or ISODate function. :-)ġ0gen has a handy SQL to Mongo Aggregation conversion chart worth bookmarking. How you convert the day of year back to a date is left as an exercise for the reader. Harmonic mean: The product of the data values divided by the number of values. You need to use $match to limit the query to the date range you are interested in and $project to rename _id to date. We can group by single as well as multiple fields from the collection. The aggregate function is used in multiple conditions. We can also use the aggregation function as well and group the method. For the purposes of example I will just write a query that gets the right counts. What is group (aggregation) In the MongoDB database, group by is used to group the data from the collection. ![]() This query is a little challenging because you want to group by date and the values stored are timestamps, so you have to do something to convert the timestamps to dates that match. More questions query to count based on condition with group by in mongodb MongoDB group by count based on condition MongoDB array of objects, count by some. New answer using Mongo aggregation frameworkĪfter this question was asked and answered, 10gen released Mongodb version 2.2 with an aggregation framework, which is now the better way to do this sort of query. The count stage returns a count of the remaining documents in the aggregation pipeline and assigns the value to a field called passingscores.
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