SELECT
     RT.Id, RT.manager_id, RT.worksite_id, RT.hire_reason_id, RT.ref, RT.notes, RT.can_claim_expenses, RT.[State]
    ,JA.org_unit_id, JA.job_position_id
--  ,RA.credential_type_id, RA.[rank], RA.essential
--  ,OA.OA_id, OA.contract_type, OA.n_vacancies

FROM OPENJSON(@JSON)
WITH
(
        id          INT
       ,manager_id  INT
       ,worksite_id INT
       ,hire_reason_id  INT
       ,ref             NVARCHAR(500)
       ,notes           NVARCHAR(500)
       ,can_claim_expenses NVARCHAR(50)
       ,[state]         NVARCHAR(50)
       ,identifiers     NVARCHAR(50)
       ,job_attributes  NVARCHAR(MAX) AS JSON
) RT
CROSS APPLY OPENJSON (RT.job_attributes)
WITH
(
     org_unit_id        INT
    ,job_position_id    INT
    ,requirements_attributes NVARCHAR(MAX) AS JSON
) JA
CROSS APPLY OPENJSON (JA.requirements_attributes)
WITH
(
     credential_type_id  INT
    ,[rank]              INT
    ,essential           BIT
    ,openings_attributes NVARCHAR(MAX) AS JSON
) RA
/*  --Uncomment #1
CROSS APPLY OPENJSON (RA.openings_attributes)
WITH
(
     OA_id          INT     '$.id'
    ,contract_type  NVARCHAR(50)
    ,n_vacancies    INT
    ,rostered_shifts_attributes NVARCHAR(MAX) AS JSON
) OA
*/
/*  --Uncomment #2
CROSS APPLY OPENJSON (OA.rostered_shifts_attributes)
WITH
(
     id         INT
    ,starts_at  datetime
    ,ends_at    datetime
    ,notes      NVARCHAR(500)
    ,on_call    BIT
)
RSA
*/
`