While you can’t get away with using only a single OPENJSON, you can simplify your query a bit to make it easier to create dynamically by removing the nested subqueries:
SELECT SectionName, SectionOrder, RenderName, RenderOrder, FieldName, FieldData
FROM OPENJSON(@layout, '$.Sections')
WITH (
SectionName NVARCHAR(MAX) '$.SectionName',
SectionOrder NVARCHAR(MAX) '$.SectionOrder',
Renders NVARCHAR(MAX) '$.Renders' AS JSON
)
CROSS APPLY OPENJSON(Renders,'$')
WITH (
RenderName NVARCHAR(MAX) '$.RenderName',
RenderOrder NVARCHAR(MAX) '$.RenderOrder',
Fields NVARCHAR(MAX) '$.Fields' AS JSON
)
CROSS APPLY OPENJSON(Fields,'$')
WITH (
FieldName NVARCHAR(MAX) '$.FieldName',
FieldData NVARCHAR(MAX) '$.FieldData'
)
If you have a primitive array, you can access the data using the value
property after you expose the nested array as a JSON field. Using the JSON from the comment below, you can do this to get the values from a primitive array:
DECLARE @layout NVARCHAR(MAX) = N'{ "id":123, "locales":["en", "no", "se"] }'
SELECT
a.id
, [Locale] = b.value
FROM OPENJSON(@layout, '$')
WITH (
id INT '$.id',
locales NVARCHAR(MAX) '$.locales' AS JSON
) a
CROSS APPLY OPENJSON(a.locales,'$') b