[SERVER-37276] Allow constant integer in $group clause - MongoDB Jira

XML

Word

Printable

Currently, $group does not allow to have a constant integer in a group clause, on the other hand, it supports strings. For example

db.foo.aggregate([{$group:{_id: {a:"$a", d:1},c: {$sum:"$c"}}}])

assert: command failed: {

    "ok" : 0,

    "errmsg" : "$group does not support inclusion-style expressions",

    "code" : 17390,

    "codeName" : "Location17390"

} : aggregate failed

If set d as a string we don't get any error

db.foo.aggregate([{$group:{_id: {a:"$a", d:"1"},c: {$sum:"$c"}}}])

In order to be consistent group should support also integer inside _id

Participants:: Andy Schwerin, Asya Kamsky, Backlog - Query Optimization, Renato Riccio