问题
I have a collection of documents :
{
"networkID": "myNetwork1",
"pointID": "point001",
"param": "param1"
}
{
"networkID": "myNetwork2",
"pointID": "point002",
"param": "param2"
}
{
"networkID": "myNetwork1",
"pointID": "point003",
"param": "param3"
}
...
pointIDs are unique but networkIDs are not.
Is it possible to query Mongodb in such a way that the result will be : [myNetwork1,myNetwork2]
right now I only managed to return [myNetwork1,myNetwork2,myNetwork1]
I need a list of unique networkIDs to populate an autocomplete select2 component. As I may have up to 50K documents I would prefer mongoDb to filter the results at the query level.
回答1:
I think you can use db.collection.distinct(fields,query)
You will be able to get the distinct values in your case for NetworkID.
It should be something like this :
Db.collection.distinct('NetworkID')
来源：https://stackoverflow.com/questions/28155857/mongodb-find-query-return-only-unique-values-no-duplicates