Mongodb C# complex query

问题

I'm kind of new to c# mongodb driver.

I have a collection which contains documents with following structure.

{
  _id          : 5a424d61f5213516a0249323,
  email        : abc@gmail.com,
  applications : [
     {
        applicationId    : 5a3b54723629c20df8bcae8d,
        applicationStatus: "Open",
        type             : "Private",
        category         : "Tech"
     },
     {
        applicationId    : 5a3b54723629c20df8bcaeasd,
        applicationStatus: "Close",
        type             : "Public",
        category         : "Agri"
     },
     {
        applicationId    : 5a3b54723629c20df8bcajkl,
        applicationStatus: "Open",
        type             : "Public",
        category         : "Business"
     },
     {
        applicationId    : 5a3b54723629c20df8bca852,
        applicationStatus: "Close",
        type             : "Public",
        category         : "Agri"
     },
  ]
}

I want to get all the documents which doesn't contain an application with category "Tech". In simple terms, I want all documents except the ones with application of category "Tech".

I've tried following query,

db.users.Find(Builders<UserModel>.Filter.And(
    Builders<UserModel>.Filter.ElemMatch(u => applications, a => a.category!= "Tech")
))

But it returns blank query Can someone teach me how to write complex query for this type of documents? Ignore my query, Suggest me standard way to get this done.

Thanks in advance. :)

回答1:

You can try with Not

db.users.Find(Builders<UserModel>.Filter.Not(Builders<UserModel>.Filter.ElemMatch(u => applications, a => a.category == "Tech")))

来源：https://stackoverflow.com/questions/48083603/mongodb-c-sharp-complex-query