DECLARE @a JSON
SET @a = JSON_OBJECTAGG( 'City':'Denver')
SELECT @@VERSION ver, @a json
ver: Microsoft SQL Server 2025 (RTM-GDR) (KB5073177) - 17.0.1050.2 (X64) Dec 15 2025 20:07:57 Copyright (C) 2025 Microsoft Corporation Enterprise Developer Edition (64-bit) on Windows 10 Pro 10.0 <X64> (Build 26200: ) (Hypervisor)
json:{"City":"Denver"}