The most efficient way to returning today's documents from a collection

Question

I have a collection where all the documents in that collection have a datetime timestamp that includes the time as well as the date.

When using the aggregation framework how do I say give me the values for today? The following only gives me the entries for midnight.

db.strategy.aggregate(
    [
        {
            $match: {
             "date": new Date()
            }
        },

    ]
);

Answer 1

To get the documents which have datetime values for today, you need to create a date query range where the start date object should hold the current date time hours at 00:00:00.000 (milliseconds precision) and set the hours for today's date to 23:59:59.999 to the end date variable.

For example:

// Create the start date which holds the beginning of today
var todayStart = new Date();
todayStart.setHours(0,0,0,0);

// Create the end date which holds the end of today
var todayEnd = new Date();
todayEnd.setHours(23,59,59,999);

// Create the date range query object
var query = {
    "date": {
        $gte: todayStart,
        $lte: todayEnd
    }
};

// using the find() method
db.strategy.find(query); 

Or using the aggregate() method as

db.strategy.aggregate({ "$match": query });