Unable to parse Json back into a table in SQL Server

Question

I have generated a Json document using FOR JSON PATH in SQL Server, however, when I try to parse it back into a table, I just get NULL .

SELECT * 
FROM OPENJSON('{"Customer":[{"CustomerID":10021,"CustomerNumber":"ALFKI","Customer":"Alfreds Futterkiste","City":"Berlin","OrderID":11060,"UnitPrice":45.6000,"ProductsOnOrder":15,"ShipCity":"Berlin"},{"CustomerID":10021,"CustomerNumber":"ALFKI","Customer":"Alfreds Futterkiste","City":"Berlin","OrderID":11061,"UnitPrice":18.0000,"ProductsOnOrder":21,"ShipCity":"Berlin"},{"CustomerID":10021,"CustomerNumber":"ALFKI","Customer":"Alfreds Futterkiste","City":"Berlin","OrderID":11062,"UnitPrice":12.0000,"ProductsOnOrder":2,"ShipCity":"Berlin"},{"CustomerID":10021,"CustomerNumber":"ALFKI","Customer":"Alfreds Futterkiste","City":"Berlin","OrderID":11187,"UnitPrice":43.9000,"ProductsOnOrder":20,"ShipCity":"Berlin"},{"CustomerID":10021,"CustomerNumber":"ALFKI","Customer":"Alfreds Futterkiste","City":"Berlin","OrderID":11217,"UnitPrice":10.0000,"ProductsOnOrder":6,"ShipCity":"Berlin"},{"CustomerID":10021,"CustomerNumber":"ALFKI","Customer":"Alfreds Futterkiste","City":"Berlin","OrderID":11218,"UnitPrice":18.0000,"ProductsOnOrder":15,"ShipCity":"Berlin"},{"CustomerID":10021,"CustomerNumber":"ALFKI","Customer":"Alfreds Futterkiste","City":"Berlin","OrderID":11554,"UnitPrice":55.0000,"ProductsOnOrder":15,"ShipCity":"Berlin"},{"CustomerID":10021,"CustomerNumber":"ALFKI","Customer":"Alfreds Futterkiste","City":"Berlin","OrderID":11555,"UnitPrice":13.0000,"ProductsOnOrder":2,"ShipCity":"Berlin"},{"CustomerID":10021,"CustomerNumber":"ALFKI","Customer":"Alfreds Futterkiste","City":"Berlin","OrderID":11846,"UnitPrice":25.0000,"ProductsOnOrder":16,"ShipCity":"Berlin"},{"CustomerID":10021,"CustomerNumber":"ALFKI","Customer":"Alfreds Futterkiste","City":"Berlin","OrderID":11847,"UnitPrice":45.6000,"ProductsOnOrder":2,"ShipCity":"Berlin"},{"CustomerID":10021,"CustomerNumber":"ALFKI","Customer":"Alfreds Futterkiste","City":"Berlin","OrderID":11992,"UnitPrice":13.2500,"ProductsOnOrder":40,"ShipCity":"Berlin"},{"CustomerID":10021,"CustomerNumber":"ALFKI","Customer":"Alfreds Futterkiste","City":"Berlin","OrderID":11993,"UnitPrice":21.5000,"ProductsOnOrder":20,"ShipCity":"Berlin"}]}')
WITH
(
    CustomerID NVARCHAR(255) '$.Customer'
)

Answer 1

Like this:

declare @json nvarchar(max) = N'{"Customer":[{"CustomerID":10021,"CustomerNumber":"ALFKI","Customer":"Alfreds Futterkiste","City":"Berlin","OrderID":11060,"UnitPrice":45.6000,"ProductsOnOrder":15,"ShipCity":"Berlin"},{"CustomerID":10021,"CustomerNumber":"ALFKI","Customer":"Alfreds Futterkiste","City":"Berlin","OrderID":11061,"UnitPrice":18.0000,"ProductsOnOrder":21,"ShipCity":"Berlin"},{"CustomerID":10021,"CustomerNumber":"ALFKI","Customer":"Alfreds Futterkiste","City":"Berlin","OrderID":11062,"UnitPrice":12.0000,"ProductsOnOrder":2,"ShipCity":"Berlin"},{"CustomerID":10021,"CustomerNumber":"ALFKI","Customer":"Alfreds Futterkiste","City":"Berlin","OrderID":11187,"UnitPrice":43.9000,"ProductsOnOrder":20,"ShipCity":"Berlin"},{"CustomerID":10021,"CustomerNumber":"ALFKI","Customer":"Alfreds Futterkiste","City":"Berlin","OrderID":11217,"UnitPrice":10.0000,"ProductsOnOrder":6,"ShipCity":"Berlin"},{"CustomerID":10021,"CustomerNumber":"ALFKI","Customer":"Alfreds Futterkiste","City":"Berlin","OrderID":11218,"UnitPrice":18.0000,"ProductsOnOrder":15,"ShipCity":"Berlin"},{"CustomerID":10021,"CustomerNumber":"ALFKI","Customer":"Alfreds Futterkiste","City":"Berlin","OrderID":11554,"UnitPrice":55.0000,"ProductsOnOrder":15,"ShipCity":"Berlin"},{"CustomerID":10021,"CustomerNumber":"ALFKI","Customer":"Alfreds Futterkiste","City":"Berlin","OrderID":11555,"UnitPrice":13.0000,"ProductsOnOrder":2,"ShipCity":"Berlin"},{"CustomerID":10021,"CustomerNumber":"ALFKI","Customer":"Alfreds Futterkiste","City":"Berlin","OrderID":11846,"UnitPrice":25.0000,"ProductsOnOrder":16,"ShipCity":"Berlin"},{"CustomerID":10021,"CustomerNumber":"ALFKI","Customer":"Alfreds Futterkiste","City":"Berlin","OrderID":11847,"UnitPrice":45.6000,"ProductsOnOrder":2,"ShipCity":"Berlin"},{"CustomerID":10021,"CustomerNumber":"ALFKI","Customer":"Alfreds Futterkiste","City":"Berlin","OrderID":11992,"UnitPrice":13.2500,"ProductsOnOrder":40,"ShipCity":"Berlin"},{"CustomerID":10021,"CustomerNumber":"ALFKI","Customer":"Alfreds Futterkiste","City":"Berlin","OrderID":11993,"UnitPrice":21.5000,"ProductsOnOrder":20,"ShipCity":"Berlin"}]}'


SELECT * 
FROM OPENJSON(@json,'$.Customer') 
      WITH
      (
        CustomerID NVARCHAR(255) '$.CustomerID'
      )

Answer 2

You need to specify a JSON Path expression in OPENJSON that selects the data you want. WITH applies to the result of the JSON Path expression.

Without it, the root object is parsed and one line returned per attribute. In this case, it's Customer with an array of values. If you used OPENJSON without a path, you'd get :

key       value              type
Customer  [{"Customer".....  4

If the root object contained another property, eg "moo":123 it would be returned in another line :

key       value              type
Customer  [{"Customer".....  4
moo       123                2

To select the contents of the Customer property, you need to use the $.Customer path. This will return the array items :

SELECT *
FROM OPENJSON(@json,'$.Customer')

Results
-------

0   {"CustomerID":10021,"CustomerN  5
1   {"CustomerID":10021,"CustomerN  5

WITH now applies to the array items and :

SELECT *
FROM OPENJSON(@json,'$.Customer')
WITH(
    CustomerID NVARCHAR(255) '$.CustomerID',
    CustomerNumber NVARCHAR(255) '$.CustomerNumber',
    Customer NVARCHAR(255) '$.Customer'
)

Will return

CustomerID  CustomerNumber  Customer
10021       ALFKI           Alfreds Futterkiste
10021       ALFKI           Alfreds Futterkiste
10021       ALFKI           Alfreds Futterkiste