Database
[{"auction_list":["key1","key2","key3","key4","key5","key6","key7","key8","key9","key10","key11","key12","key13","key14"]},{"auction_list":["key1","key2","key3","key4","key5","key6","key7","key8","key9","key10","key11","key12","key13","key14"]},{"auction_list":["key1","key2","key3","key4","key5","key6","key7","key8","key9","key10","key11","key12","key13","key14"]}]
Query
db.collection.aggregate([{$project:{_id:0,slicedArray:{$slice:["$auction_list",10]}}}])