mongodb-query

In aggregation i am trying to project an object(which is an array) which is present at position 7 inside an array . For example i have fields as below { "$project": { "result": { "$cond": { "if": { "$eq": ["$coupon_type", 1] }, "then": ["$_id", "$coupon_type", "$nonce", "$total_coupons", "$amount", "$curr_ctr"], "else": ["$_id", "$coupon_type", "$nonce", "$total_coupons", "$amount", "$curr_ctr", "$coupon_codes", { indexes: conditions }] } } } }, { "$project": { obj: { $arrayElemAt: [ "$result", 7 ] } // here how to project indexes. } So now for coupon_type: 0 i will project my result as ["$_id

I'm attempting to write a query to return the top X terms across each category - e.g. top 5, top 10 etc. Each term has an associated category, and based up on some help from another stackoverflow question I've managed to get this: db.collection.aggregate([ { $group : { _id : { category: "$uri.category", term: "$uri.term", }, total: { $sum : 1 } } }, { $sort : { total : -1 } }, { $group : { _id : "$_id.category", terms: { $push: { term: "$_id.term", total: "$total" } } } } ]); The above query does work, and returns data that looks something like this: [ { category: "movies", terms: [ { term: