sql MS SQL JSON_VALUE

Posted 2021-05-13

DECLARE @browsers NVARCHAR(1000)
    = N'
{ "Browsers": [
    { 
      "Name": "Firefox", 
      "Info": { "Version": "1.0.1", "Category": "Major" },
      "LogDate": 2003, "AddedOn": "2004-11-09" \
    },
    {
      "Name": "Opera", 
      "Info": { "Version": "1.0.5", "Category": "Dev" },
      "LogDate": 2004, "AddedOn": "2008-11-09" 
    }] 
}';

-- Name of the first item
SELECT JSON_VALUE(@browsers, '$.Browsers[0].Name');
-- Output: Firefox

-- Return the Added On Date of the first browser in our array 
-- and convert it into a DateTime2 datatype
SELECT CAST(JSON_VALUE(@browsers,
              '$.Browsers[0].AddedOn') AS DATETIME2);
-- Output: 2004-11-09 00:00:00.0000000

-- This returns NULL because the 'Browsers' is 
-- an array instead of a simple object
SELECT JSON_VALUE(@browsers, '$.Browsers');
-- Output: NULL

-- This is also invalid because JSON_VALUE cannot return
-- an array...only scalar values allowed!
SELECT JSON_VALUE(@browsers, '$.Browsers[1].Info');
-- Output: NULL

-- Much better
SELECT JSON_VALUE(@browsers, '$.Browsers[1].Info.Category');
-- Output: Dev