Not Getting the Shape Right in DocumentDb Select - azure

Question

I'm trying to get only the person's membership info i.e. ID, name and committee memberships in a SELECT query. This is my object:
{
"id": 123,
"name": "John Smith",
"memberships": [
{
"id": 789,
"name": "U.S. Congress",
"yearElected": 2012,
"state": "California",
"committees": [
{
"id": 444,
"name": "Appropriations Comittee",
"position": "Member"
},
{
"id": 555,
"name": "Armed Services Comittee",
"position": "Chairman"
},
{
"id": 678,
"name": "Veterans' Affairs Comittee",
"position": "Member"
}
]
}
]
}
In this example, John Smith is a member of the U.S. Congress and three committees in it.
The result that I'm trying to get should look like this. Again, this is the "DESIRED RESULT":
{
"id": 789,
"name": "U.S. Congress",
"committees": [
{
"id": 444,
"name": "Appropriations Committee",
"position": "Member"
},
{
"id": 555,
"name": "Armed Services Committee",
"position": "Chairman"
},
{
"id": 678,
"name": "Veterans' Affairs Committee",
"position": "Member"
}
]
}
Here's my SQL query:
SELECT m.id, m.name,
[
{
"id": c.id,
"name": c.name,
"position": c.position
}
] AS committees
FROM a
JOIN m IN a.memberships
JOIN c IN m.committees
WHERE a.id = "123"
I'm getting the following results which is correct but the shape is not right. I'm getting the same membership 3 times. Here's what I'm getting which is NOT the desired result:
[
{
"id": 789,
"name": "U.S. Congress",
"committees":[
{
"id": 444,
"name": "Appropriations Committee",
"position": "Member"
}
]
},
{
"id": 789,
"name": "U.S. Congress",
"committees":[
{
"id": 555,
"name": "Armed Services Committee",
"position": "Chairman"
}
]
},
{
"id": 789,
"name": "U.S. Congress",
"committees":[
{
"id": 678,
"name": "Veterans' Affairs Committee",
"position": "Member"
}
]
}
]
As you can see here, the "U.S. Congress" membership is repeated 3 times.
The following SQL query gets me exactly what I want in Azure Query Explorer but when I pass it as the query in my code -- using DocumentDb SDK -- I don't get any of the details for the committees. I simply get blank results for committee ID, name and position. I do, however, get the membership data i.e. "U.S. Congress", etc. Here's that SQL query:
SELECT m.id, m.name, m.committees AS committees
FROM c
JOIN m IN c.memberhips
WHERE c.id = 123
I'm including the code that makes the DocumentDb call. I'm including the code with our internal comments to help clarify their purpose:
First the ReadQuery function that we call whenever we need to read something from DocumentDb:
public async Task<IEnumerable<T>> ReadQuery<T>(string collectionId, string sql, Dictionary<string, object> parameterNameValueCollection)
{
// Prepare collection self link
var collectionLink = UriFactory.CreateDocumentCollectionUri(_dbName, collectionId);
// Prepare query
var query = getQuery(sql, parameterNameValueCollection);
// Creates the query and returns IQueryable object that will be executed by the calling function
var result = _client.CreateDocumentQuery<T>(collectionLink, query, null);
return await result.QueryAsync();
}
The following function prepares the query -- with any parameters:
protected SqlQuerySpec getQuery(string sql, Dictionary<string, object> parameterNameValueCollection)
{
// Declare query object
SqlQuerySpec query = new SqlQuerySpec();
// Set query text
query.QueryText = sql;
// Convert parameters received in a collection to DocumentDb paramters
if (parameterNameValueCollection != null && parameterNameValueCollection.Count > 0)
{
// Go through each item in the parameters collection and process it
foreach (var item in parameterNameValueCollection)
{
query.Parameters.Add(new SqlParameter($"#{item.Key}", item.Value));
}
}
return query;
}
This function makes async call to DocumentDb:
public async static Task<IEnumerable<T>> QueryAsync<T>(this IQueryable<T> query)
{
var docQuery = query.AsDocumentQuery();
// Batches gives us the ability to read data in chunks in an asyc fashion.
// If we use the ToList<T>() LINQ method to read ALL the data, the call will synchronous which is why we prefer the batches approach.
var batches = new List<IEnumerable<T>>();
do
{
// Actual call is made to the backend DocumentDb database
var batch = await docQuery.ExecuteNextAsync<T>();
batches.Add(batch);
}
while (docQuery.HasMoreResults);
// Because batches are collections of collections, we use the following line to merge all into a single collection.
var docs = batches.SelectMany(b => b);
// Return data
return docs;
}

Answer 1

I just write a demo to test with your query and I can get the expected result, check the snapshot below. So I think that query is correct, you've mentioned that you don't seem to get any data when you make the call in my code, would you mind share your code? Perhaps there are some mistakes in you code. Anyway, here is my test just for your reference and hope it helps.
Query used:
SELECT m.id AS membershipId, m.name AS membershipNameName, m.committees AS committees
FROM c
JOIN m IN c.memberships
WHERE c.id = "123"
Code here is very simple, sp_db.innerText represents a span which I used to show the result in my test page:
var docs = client.CreateDocumentQuery("dbs/" + databaseId + "/colls/" + collectionId,
"SELECT m.id AS membershipId, m.name AS membershipName, m.committees AS committees " +
"FROM c " +
"JOIN m IN c.memberships " +
"WHERE c.id = \"123\"");
foreach (var doc in docs)
{
sp_db.InnerText += doc;
}
I think maybe there are some typos in the query you specified in client.CreateDocumentQuery() which makes the result to be none, it's better to provide the code for us, then we can help check it.
Updates:
Just tried your code and still I can get the expected result. One thing I found is that when I specified the where clause like "where c.id = \"123\"", it gets the result:
However, if you didn't make the escape and just use "where c.id = 123", this time you get nothing. I think this could be a reason. You can verify whether you have ran into this scenario.

Answer 2

Just updated my original post. All the code provided in the question is correct and works. I was having a problem because I was using aliases in the SELECT query and as a result some properties were not binding to my domain object.
The code provided in the question is correct.