WHERE clause on an array in Azure DocumentDb - azure-cosmosdb

Question

In an Azure Documentdb document like this
{
"id": "WakefieldFamily",
"parents": [
{ "familyName": "Wakefield", "givenName": "Robin" },
{ "familyName": "Miller", "givenName": "Ben" }
],
"children": [
{
"familyName": "Merriam",
"givenName": "Jesse",
"gender": "female",
"grade": 1,
"pets": [
{ "givenName": "Goofy" },
{ "givenName": "Shadow" }
]
},
{
"familyName": "Miller",
"givenName": "Lisa",
"gender": "female",
"grade": 8
}
],
"address": { "state": "NY", "county": "Manhattan", "city": "NY" },
"isRegistered": false
};
How do I query to get children whose pets given name is "Goofy" ?
Looks like the following syntax is invalid
Select * from root r
WHERE r.children.pets.givenName="Goofy"
Instead I need to do
Select * from root r
WHERE r.children[0].pets[0].givenName="Goofy"
which is not really searching through an array.
Any suggestion on how I should handle queries like these ?

Answer 1

You should take advantage of DocumentDB's JOIN clause, which operates a bit differently than JOIN in RDBMs (since DocumentDB deals w/ denormlaized data model of schema-free documents).
To put it simply, you can think of DocumentDB's JOIN as self-joins which can be used to form cross-products between nested JSON objects.
In the context of querying children whose pets given name is "Goofy", you can try:
SELECT
f.id AS familyName,
c AS child,
p.givenName AS petName
FROM Families f
JOIN c IN f.children
JOIN p IN c.pets
WHERE p.givenName = "Goofy"
Which returns:
[{
familyName: WakefieldFamily,
child: {
familyName: Merriam,
givenName: Jesse,
gender: female,
grade: 1,
pets: [{
givenName: Goofy
}, {
givenName: Shadow
}]
},
petName: Goofy
}]
Reference: http://azure.microsoft.com/en-us/documentation/articles/documentdb-sql-query/
Edit:
You can also use the ARRAY_CONTAINS function, which looks something like this:
SELECT food.id, food.description, food.tags
FROM food
WHERE food.id = "09052" or ARRAY_CONTAINS(food.tags.name, "blueberries")

Answer 2

I think the ARRAY_CONTAINS function has changed since this was answered in 2014. I had to use the following for it to work.
SELECT * FROM c
WHERE ARRAY_CONTAINS(c.Samples, {"TimeBasis":"5MIN_AV", "Value":"5.105"},true)
Samples is my JSON array and it contains objects with many properties including the two above.