MongoDB: get documents by tags

Question

I\'ve got documents containing tags array. I want to provide tags based recommendations on site, so I need to get documents containing same tags + documents tha

Answer 1

Steps:

1. Find matching products which contains any of the specified keys.

2. Unfold on keys

3. Do find again to filter unwanted after unfolding

4. Group them by adding key occurrence

5. Sort desc to get most relevant first

[{ "$match" : { "keys" : { "$in" : [ { "$regex" : "text" , "$options" : "i"}]}}}, { "$unwind" : "$keys"}, { "$match" : { "keys" : { "$in" : [ { "$regex" : "text" , "$options" : "i"}]}}}, { "$group" : { "_id" : { "productId" : "$productId"} , "relatedTags" : { "$sum" : 1} }}, { "$sort" : { "relatedTags" : -1}},{ "$limit" : 10}]