JSON_QUERY to do a "Select Many" - json

Question

I have a JSON variable that looks like this (the real one is more complex):
DECLARE #myJson VARCHAR(3000) = '{
"CustomerId": "123456",
"Orders": [{
"OrderId": "852",
"OrderManifests": [{
"ShippedProductId": 884,
"ProductId": 884
}, {
"ShippedProductId": 951,
"ProductId": 2564
}
]
}, {
"OrderId": "5681",
"OrderManifests": [{
"ShippedProductId": 198,
"ProductId": 4681
}, {
"ShippedProductId": 8188,
"ProductId": 8188
}, {
"ShippedProductId": 144,
"ProductId": 8487
}
]
}
]
}'
In the end, I need to know if any of the ShippedProductId values match their corresponding ProductId (in the same JSON object).
I started in by trying to get a list of all the OrderManifests. But while this will get me the array of orders:
SELECT JSON_QUERY(#myJson, '$.Orders')
I can't seem to find a way to get a list of all the OrderManifests across all the entries in the Orders array. This does not work:
SELECT JSON_QUERY(#myJson, '$.Orders.OrderManifests')
Is there a way to do a Select Many kind of query to get all the OrderManifests in the Orders array?

Answer 1

Use OPENJSON and CROSS APPLY to drill down into your objects.
This should do it for you:
SELECT j.CustomerId,o.OrderId, m.ShippedProductId, m.ProductId
FROM OPENJSON(#myJson)
WITH (
CustomerId NVARCHAR(1000),
Orders NVARCHAR(MAX) AS JSON
) j
CROSS APPLY OPENJSON(j.Orders)
WITH (
OrderId NVARCHAR(1000),
OrderManifests NVARCHAR(MAX) AS JSON
) o
CROSS APPLY OPENJSON(o.OrderManifests)
WITH (
ShippedProductId INT,
ProductId int
) m
WHERE m.ShippedProductId = m.ProductId;
This query returns:
CustomerId | OrderId | ShipedProductId | ProductId
------------+-----------+-------------------+-------------
123456 | 852 | 884 | 884
------------+-----------+-------------------+-------------
123456 | 5681 | 8188 | 8188