OPENJSON on JSON with double empty array - json

Question

I have this JSON
{
"OrderHeader": [[
{
"OrderID": 100,
"CustomerID": 2000,
"OrderDetail":
{
"ProductID":2000,
"UnitPrice":350
}
}
]]
}
After the OrderHeader there is two [[.
I am not able to parse this JSON using the OPENJSON TSQL Command.
If it was just one [ then i would parse like
DECLARE #JSONData varchar(MAX) = '
{
"OrderHeader": [
{
"OrderID": 100,
"CustomerID": 2000,
"OrderDetail":
{
"ProductID": 2000,
"UnitPrice": 350
}
}
]
}
'
SELECT
OrderID, CustomerID, ProductID, UnitPrice
FROM OPENJSON (#JSONData)
WITH (
OrderHeader nvarchar(MAX) AS JSON
) AS Orders
CROSS APPLY OPENJSON(Orders.OrderHeader)
WITH
(
OrderID INT,
CustomerID INT,
OrderDetail nvarchar(MAX) AS JSON
) AS OrderDetail
CROSS APPLY OPENJSON(OrderDetail.OrderDetail)
WITH
(
ProductID INT,
UnitPrice INT
) ;
Please help to Parse with its with TWO [ as in the first sample
Thank you.

Answer 1

One method would be to double up the OPENJSONs, though I would personally suggest, if you can, fixing the JSON:
DECLARE #JSONData nvarchar(MAX) = N'
{
"OrderHeader": [[
{
"OrderID": 100,
"CustomerID": 2000,
"OrderDetail":
{
"ProductID": 2000,
"UnitPrice": 350
}
}
]]
}';
SELECT V.OrderID,
V.CustomerID,
OD.ProductID,
OD.UnitPrice
FROM OPENJSON(#JSONData)
WITH (OrderHeader nvarchar(MAX) AS JSON) OJ
CROSS APPLY OPENJSON(OJ.OrderHeader) OH
CROSS APPLY OPENJSON(OH.[value])
WITH (OrderID int,
CustomerID int,
OrderDetail nvarchar(MAX) AS JSON) V
CROSS APPLY OPENJSON(V.OrderDetail)
WITH (ProductID int,
UnitPrice int) OD;

Answer 2

The statement depends on the structure of the parsed JSON ( ... I hope I understand it correctly) and you may simplify your statement using only two OPENJSON() calls:
JSON (with one additional item in the nested JSON array):
DECLARE #JSONData varchar(MAX) = '
{
"OrderHeader": [[
{
"OrderID": 100,
"CustomerID": 2000,
"OrderDetail":
{
"ProductID":2000,
"UnitPrice":350
}
},
{
"OrderID": 200,
"CustomerID": 3000,
"OrderDetail":
{
"ProductID":2000,
"UnitPrice":350
}
}
]]
}'
Statement:
SELECT j2.*
FROM OPENJSON(#JSONData, '$.OrderHeader') j1
CROSS APPLY OPENJSON(j1.[value]) WITH (
OrderID INT '$.OrderID',
CustomerID INT '$.CustomerID',
ProductID INT '$.OrderDetail.ProductID',
UnitPrice INT' $.OrderDetail.UnitPrice'
) j2
Result:
OrderID CustomerID ProductID UnitPrice
100 2000 2000 350
200 3000 2000 350
Finally, if the $.OrderHeader JSON array always has a single item, the following statement is also an option:
SELECT *
FROM OPENJSON(#JSONData, '$.OrderHeader[0]') WITH (
OrderID INT '$.OrderID',
CustomerID INT '$.CustomerID',
ProductID INT '$.OrderDetail.ProductID',
UnitPrice INT' $.OrderDetail.UnitPrice'
)