Find all documents within last n days

Question

My daily collection has documents like:

..
{ \"date\" : ISODate(\"2013-01-03T00:00:00Z\"), \"vid\" : \"ED\", \"san\" : 7046.25, \"izm\" : 12         


        

Answer 1

You need to run the distinct command to get all the unique dates. Below is the example. The "values" array has all the unique dates of the collection from which you need to retrieve the most recent 15 days on the client side

db.runCommand ( { distinct: 'datecol', key: 'date' } )
{
    "values" : [
       ISODate("2013-01-03T00:00:00Z"),
       ISODate("2013-01-04T00:00:00Z")
    ],
    "stats" : {
       "n" : 2,
       "nscanned" : 2,
       "nscannedObjects" : 2,
       "timems" : 0,
       "cursor" : "BasicCursor"
    },
    "ok" : 1
}

You then use the $in operator with the most recent 15 dates from step 1. Below is an example that finds all documents that belong to one of the mentioned two dates.

db.datecol.find({
  "date":{
     "$in":[
        new ISODate("2013-01-03T00:00:00Z"), 
        new ISODate("2013-01-04T00:00:00Z")
      ]
  }
})