SQL Server 2019

By using db<>fiddle, you agree to license everything you submit by Creative Commons CC0.
CREATE TABLE [dbo].[CitiesTable] ([CitiesJson] [NVARCHAR](MAX) NOT NULL) ON [PRIMARY];
INSERT INTO [dbo].[CitiesTable] ([CitiesJson]) VALUES ('{"cities":[{"cityName": "London","residentCount": 8961989},{"cityName": "Paris","residentCount": 2165423},{"cityName": "Berlin","residentCount": 3664088}]}');
1 rows affected

SELECT x.[CityName], x.[ResidentCount]
FROM
    OPENJSON((SELECT [CitiesJson] FROM dbo.CitiesTable), '$.cities') 
    WITH 
    (
        [CityName] [NVARCHAR] (50) '$.cityName',
        [ResidentCount] [INT] '$.residentCount'
    ) AS x


CityName
ResidentCount


London
8961989

Paris
2165423

Berlin
3664088


CREATE VIEW [dbo].[Cities_IndexedView]
WITH SCHEMABINDING
AS
SELECT x.[CityName], x.[ResidentCount]
FROM
    OPENJSON((SELECT [CitiesJson] FROM dbo.CitiesTable), '$.cities') 
    WITH 
    (
        [CityName] [NVARCHAR] (10) '$.cityName',
        [ResidentCount] [INT] '$.residentCount'
    ) AS x
CREATE UNIQUE CLUSTERED INDEX Cities_IndexedView_ucidx on dbo.Cities_IndexedView([CityName]);
Msg 10148 Level 16 State 1 Line 1
Cannot create index on the view 'fiddle_cf57a9b555f74ea1ada4c5d0d277cf95.dbo.Cities_IndexedView' because it uses OPENJSON.

DROP VIEW IF EXISTS [dbo].[Cities_IndexedView];

DROP TABLE IF EXISTS [dbo].[CitiesTable];