SQL Server - OPENJSON output with an explicit schema - arrays

Question

I have the below array of an HTTP request, in JSON format:
[
{
"Code":"856956645",
"Type":"Colet",
"MeasuredWeight":0.0,
"VolumetricWeight":0.0,
"ConfirmationName":null,
"Observation":" 100 DE SFATURI OASELE",
"ResponseCode":null,
"Event":
[
{
"Date":"2018-11-16T16:22:29.397",
"EventId":73,
"Description":"Ridicare din comanda client",
"LocalityName":"BUCURESTI"
},
{
"Date":"2018-11-17T08:55:06.14",
"EventId":5,
"Description":"Spre destinatar ",
"LocalityName":"BUCURESTI"
}
]
}
]
How could I extract the value of Description element, within the second set of values. I tried with OPENJSON but I couldn't do it:
SELECT *
FROM OPENJSON(#json)
WITH (
Description nvarchar(100) '$.Event.Description'
);

Answer 1

Try nesting instead. Nor sure why your attempt didn't work; I've not had much use for OPENJSON as yet apart from when playing around, however, this works:
SELECT J.Code, J.[Type], E.[Description]
FROM OPENJSON(#json)
WITH (Code bigint '$.Code',
[Type] varchar(10) '$.Type',
[Event] nvarchar(MAX) AS JSON) J
CROSS APPLY OPENJSON([Event])
WITH ([Description] varchar(100) '$.Description',
EventID int '$.EventId') E
WHERE E.EventID = 5;
Edit: Worked out why your attempt wasn't working. The JSON you have has a new JSON object in the Event node, they're not simply properties, like in the documentation's second example here. The entities are wrapped in further brackets ([]), not just braces ({}), and hence why you have to parse the next layer again as a separate JSON object.