Azure Cosmos DB - count nested keys in subdocument

Question

Having a Cosmos DB document with below schema:

{
  id: 1,
  nested: {
    key1: true,
    key2: false
  }
}

Is there any SQL operator I could use to count the keys in the "nested" subdocument? Similar to Object.keys(nested).length in JavaScript

Answer 1

You can write Cosmos Db UDF to get count of nested keys document.

I have tried using sample data posted in question.

UDF Code

function getLength(nested) {
return  Object.keys(nested).length;
}

Query to consume UDF

SELECT udf.getLength(c.nested) AS LengthOfKeys FROM c

Here is result of the above query.

Sample data

{
"id": "1",
"nested": {
"key1": true,
"key2": false
}
{
"id": "2",
"nested": {
"key1": true,
"key2": false,
"key3": "hello"
}