I replace MongoDB default _id with type string. And now I want to sort my collections, the result _id after sort is:
1
10
100
101
2
20
200
I want the result like sorting number which is:
1
2
3
4
5
What's my option? Is there any way to sort the string like number? Or I have to change my _id type?
What's my option? Is there any way to sort the string like a number?
Yes, you have an option to sort string like a number, but in all your queries you need to convert your string field to an integer field just for sorting and it is not recommended.
db.collection.aggregate(
[
{
'$addFields': {
'_id': {
'$toInt': '$_id'
}
}
}, {
'$sort': {
'_id': 1
}
}
]
)
Or I have to change my _id type?
Yes, you need to change the type of _id field from string to integer as a permanent solution. Since _id filed is an immutable field, you cannot directly convert the data of _id field from string to integer. you need to remove all your documents and insert with the corrected data type.
