查询 cosmos db 文档来过滤文档

Question

I am reading all documents from my cosmos db sql api collection and I would like to filter out those documents which has a specific property defined in the json. So if documents are of this schema

{
id: 1
name: aaa
project: ssdf
}

I would like to filter out documents which has "project" property in it. My code till now where I am able to read documents from collection:

 do
            {
                var feed = await client.ReadDocumentFeedAsync(
                    UriFactory.CreateDocumentCollectionUri( SourceDatabase, SourceCollection ),
                    new FeedOptions { MaxItemCount = 10, RequestContinuation = continuationToken } );
                continuationToken = feed.ResponseContinuation;
                foreach( Document document in feed )
                {
                    Console.WriteLine( document );
                }
            } 

The query by which I get filtered documents in Cosmos db is select * FROM c WHERE IS_DEFINED(c.Project) . How do I do it in code above?

Updating Question after Gaurav's answer:

static async Task Main()
        {
            string continuationToken = null;
            DocumentClient client = new DocumentClient( new Uri( endpointUrl ), authorizationKey );
            var feed = client.CreateDocumentQuery(
                       UriFactory.CreateDocumentCollectionUri( SourceDatabase, SourceCollection ).ToString(),
                       new SqlQuerySpec( "select * FROM c WHERE IS_DEFINED(c.Project)" ),

                       new FeedOptions { MaxItemCount = 100, EnableCrossPartitionQuery=true } ) ;
            continuationToken = feed.
                
                foreach( Document document in feed )
                {
                   
                   Console.WriteLine( document.Id );
                }

Answer 1

I believe you're using version 2.0 of the Cosmos DB SDK. If that's the case, then you can use CreateDocumentQuery(String, String, FeedOptions) method to execute a query.

Here's an example to do the same:

// SQL querying allows dynamic property access
dynamic document = client.CreateDocumentQuery<dynamic>(collectionLink,
    "SELECT * FROM books b WHERE b.title == 'War and Peace'").AsEnumerable().FirstOrDefault();

It is highly recommended that you start using SDK version 3.0 as all the new features are/will be available in the new SDK.

UPDATE

Please see code below. It fetches 100 documents from collection at a time.

using System;
using Microsoft.Azure.Documents;
using Microsoft.Azure.Documents.Client;
using Microsoft.Azure.Documents.Linq;

namespace SO68439632
{
    class Program
    {
        static void Main(string[] args)
        {
            var endpointUrl = "https://accountname.documents.azure.com:443/";
            var authorizationKey = "authorizationkey==";
            DocumentClient client = new DocumentClient(new Uri(endpointUrl), authorizationKey);
            var databaseId = "database-name";
            var containerId = "container-name";

            string continuationToken = null;
            string collectionUrl = UriFactory.CreateDocumentCollectionUri(databaseId, containerId).ToString();
            do
            {
                var feed = client.CreateDocumentQuery(
                           collectionUrl,
                           new SqlQuerySpec("select * FROM c WHERE c.Level = 2"),
                           new FeedOptions { MaxItemCount = 100, EnableCrossPartitionQuery = true, RequestContinuation = continuationToken }).AsDocumentQuery();
                var result = feed.ExecuteNextAsync().Result;
                continuationToken = result.ResponseContinuation;
                var itemsCount = result.Count;
                Console.WriteLine(string.Format("Total items fetched: {0}; More results available: {1}", itemsCount, !string.IsNullOrWhiteSpace(continuationToken)));
            }
            while (continuationToken != null);
        }
    }
}