Azure Data Factory - SQL to nested JSON

Question

I have a SQL database with tables for Staff and Appointments (1 staff : many appointments). I'd like to use Azure Data Factory to output this to nested JSON in a Blob store in a format similar to the below:

[
   {
      "staffid":"101",
      "firstname":"Donald",
      "lastname":"Duck",
      "appointments":[
         {
            "appointmentid":"201",
            "startdate":"2020-02-01T00:00:00",
            "enddate":"2020-04-29T23:00:00"
         },
         {
            "appointmentid":"202",
            "startdate":"2020-01-01T00:00:00",
            "enddate":"2020-01-31T00:00:00"
         }
      ]
   },
   {
      "staffid":"102",
      "firstname":"Mickey",
      "lastname":"Mouse",
      "appointments":[
         {
            "appointmentid":"203",
            "startdate":"2020-02-01T00:00:00",
            "enddate":"2020-04-29T23:00:00"
         },
         {
            "appointmentid":"204",
            "startdate":"2020-01-01T00:00:00",
            "enddate":"2020-01-31T00:00:00"
         }
      ]
   }
]

I've tried using the Copy activity but this produces flat JSON structures rather than the nested structure described above. Has anyone got a way to do this please?

Answer 1

More scenarios for JSON data in ADF is flattening. However,according to your description,your need producing JSON contains Json array group by some columns.Something like merge appointment things by same staff .

If my understanding is right,then you could get some clues from my previous case: How to split into Sub Documents with Nesting separator? . Please refer to my test:

Simulate your sample data:

Use sql in sql db source dataset:

select app.staffid,app.firstname,app.lastname,
'appointments' = (
            SELECT
                appointmentid AS 'appointmentid',startdate as 'startdate',enddate as 'enddate'
            FROM
                dbo.appoint as app2
            where app2.staffid = app.staffid and
            app2.firstname = app.firstname and
            app2.lastname = app.lastname
            FOR JSON PATH)
from dbo.appoint as app
group by app.staffid,app.firstname,app.lastname
FOR JSON Path;

Output in blob storage:

I try to verify the json format and it is correct.