Cosmos DB Query Projection - azure-cosmosdb

Question

I have Cosmos Document of below format:
(Note: Example is just for illustration, the actual document has different properties)
{
"OrderNumer":"12345",
"Version":"5",
"OrderDetails": [
{
"id":1,
"OrderItem": {
"Name": "ABC",
"Description": "ABC Description",
.
.
.
},
"PaymentDetails": {
},
.
.
.
},
{
"id":2,
"OrderItem": {
"Name": "PQR",
"Description": "PQR Description",
.
.
.
},
"PaymentDetails": {
},
.
.
.
},
],
"OrderDate": "12-01-2020",
"CustomerDetails": {
}
.
.
.
}
OrderNumber is a partition key.
I'm trying to project the above document through Cosmos Query to get the entire OrderDetails JSON object and a few properties from the parent into a single JSON with a filter on OrderDetails-> id.
The expected projection should be:
{
"Order":
[
{
"OrderNumer":"12345",
"Version":"5",
"id":1,
"OrderItem": {
"Name": "ABC",
"Description": "ABC Description",
.
.
.
},
"PaymentDetails": {
},
.
.
.
},
{
"OrderNumer":"12345",
"Version":"5",
"id":2,
"OrderItem": {
"Name": "PQR",
"Description": "PQR Description",
.
.
.
},
"PaymentDetails": {
},
.
.
.
},
]
}
As shown in the above JSON, I'm projecting OrderNumber and Version properties within the OrderDetails as Order.
OrderDetails is a massive JSON with a dynamic schema that makes it difficult for us to project its properties individually.
I have tried a few options to project this, but the closest I could reach was below query:
SELECT c.OrderNumber, c.Version, o as Order
FROM c
JOIN o in c.OrderDetails WHERE
c.OrderNumber= '1235' AND ARRAY_CONTAINS([1,2], o.id)
However, the above query does not give desired result as it keeps the OrderNumber and Version in as separate property to Order.
Is there any way I can achieve this?

Answer 1

You can use UDF.
First:create a udf,below is code
function Converted(version,orderNumber,orderItem){
orderItem.Version = version;
orderItem.OrderNumber = orderNumber;
return orderItem;
}
Second:use this sql
select value udf.Converted(c.Version,c.OrderNumber,o) from c join o in c.OrderDetails WHERE c.OrderNumber= '12345' AND ARRAY_CONTAINS([1,2], o.id)
Finally:new JsonObject add this result via code.
Here is result:
[
{
"id": 1,
"OrderItem": {
"Name": "ABC",
"Description": "ABC Description"
},
"PaymentDetails": {},
"Version": "5",
"OrderNumber": "12345"
},
{
"id": 2,
"OrderItem": {
"Name": "PQR",
"Description": "PQR Description"
},
"PaymentDetails": {},
"Version": "5",
"OrderNumber": "12345"
}
]
Does this meet your requirements?

Answer 2

I know this is too late to answer, till now you have resolved your problem but still providing the query to help other people who may have faced a similar issue.
CosmosDB provides flexibility which will help you to modify output JSON structure. Please see the below query for above problem.
Query:
SELECT
[
{
"OrderNumer": c.OrderNumer,
"Version": c.Version,
"id": od.id,
"OrderItem": {
"Name": od.OrderItem.Name,
"Description": od.OrderItem.Description
}
}
] AS Orders
FROM c
JOIN od IN c.OrderDetails
Happy coding!