Mongo sort by string value that is actually number - mongodb

Question

I have collection that contains objects such as this:
{
"_id" : ObjectId("57f00cf47958af95dca29c0c"),
"id" : "...",
"threadId" : "...",
"ownerEmail" : "...#...",
"labelIds" : [
...
],
"snippet" : "...",
"historyId" : "35699995",
"internalDate" : "1422773000000",
"headers" : {
"from" : "...#...",
"subject" : "....",
"to" : "...#..."
},
"contents" : {
"html" : "...."
}
}
When accessing objects, I want to sort them by iternalDate value, which was supposed to be integer, however it is a string. Is there a way to sort them when fetching even if these are strings? By alphabetic order? Or is there a way to convert them to integer painlessly?

Answer 1

Collation is what you need...
db.collection.find()
.sort({internalDate: 1})
.collation({locale: "en_US", numericOrdering: true})

Answer 2

It seems to me that the best solution here would be to parse it first as an integer. You could do it using a simple script in javascript like this, using the mongodb client for node:
db.collection.find({}, {internalDate: 1}).forEach(function(doc) {
db.collection.update(
{ _id: doc._id },
{ $set: { internalDate: parseInt(doc.internalDate) } }
)
})

Answer 3

you also can use the aggregate method to sort number which is actually a string.
db.collection.aggregate([{
$sort : {
internalDate : 1
}
}], {
collation: {
locale: "en_US",
numericOrdering: true
}
});
if you are using mongoose-paginate package for serverside pagination .. so don't use this package, use only mongoose-paginate-v2 for serverside pagination. this package for nodejs side

Answer 4

I was having this issue. I use string length to sort first and then apply the sort of my numeric value stored like a string. e.g. "1", "100", "20", "3" that should be sorted like 1, 3, 29, 100.
db.AllTours.aggregate([
{
$addFields : {
"MyStringValueSize" : { $strLenCP: "$MyValue" }
}
},
{
$sort : {
"MyStringValueSize" : 1,
"MyValue" : 1
}
}
]);
There is a new feature in version 4.0 called $toInt that can be used to parse your string and then sort. In my case I can't upgrade from 3.6.

Answer 5

With aggregate, this works for me.
db.collection.aggregate([<pipeline>]).collation({locale:"en_US", numericOrdering:true})

Answer 6

This is my solution and it worked for me
db.getCollection('myCollection').aggregate([
{
$project: {
newMonth: {
$cond: { if: {
$and: [
{$ne: ['$month', '10']},
{$ne: ['$month', '11']},
{$ne: ['$month', '12']},
]
}, then: {$concat: ['0', '$month']}, else: '$month' }
}
}
},
{
$sort: {newMonth: -1}
}
])