I have the following document in MongoDB.
{
"_id" : ObjectId("5d5f9a3056be496aec564bca"),
"field1" : "value1",
"field2" : "value2",
}
How can I query this and get the ObjectId as String. like below
{
"_id" : "5d5f9a3056be496aec564bca",
"field1" : "value1",
"field2" : "value2",
}
You can use $toString operator to do this task.
db.collection.aggregate([
{
$project: {
_id: {
$toString: "$_id",
},
field1: 1,
field2: 1
}
}
])
On MongoDB version >= 4.0 - You'll have an option to convert the type of the field, Here you can use $toString to convert it to string :
db.collection.aggregate([
/** `$addFields` will overwrite the existing value of field if a field exists with same name,
* if not will create a new additional field on doc */
{
$addFields: {
_id: {
$toString: "$_id"
}
}
}
])
Test : mongoplayground
Note : On version below 4.0 there is no way to convert ObjectId() to string using MongoDB query unless you use any code to do it.
ObjectId() to String in query for version prior to 4.0 but when you read results in code as ObjectId() is not a supported type of JSON it will by default be converted to string !! But converting in query is not possible..ObjectId() to String in code ?