Mongodb and sorting sub array

Question

Not sure if this can be done, so thought I would ask.

I have the following mongodb/s

{
 \"store\":\"abc\",
 \"offers\":[{
    \"spend\":\"100.00\",
          


        

Answer 1

Given your data structure of arrays within documents, I don't think it makes sense to do this sort in MongoDB -- Mongo will be returning entire documents (not arrays).

If you are trying to compare offers it would probably make more sense to have a separate collection instead of an embedded array. For example, you could then find offers matching a cashback of at least $5 sorted by spend or percentage discount.

If you are just trying to order the offers within a single document, you could do this in PHP with a usort().

Answer 2

Amazingly, yes, mongodb can do this:

// Sort ascending, by minimum percentage value in the docs' offers array.
db.collection.find({}).sort({ 'offers.percentage': 1 });

// Sort descending, by maximum percentage value in the docs' offers array.
db.collection.find({}).sort({ 'offers.percentage': -1 });