Pivot TSQL table with dynamic columns

Question

I am passing up JSON as a parameter to a SQL stored proc. I use a function that takes a JSON dictionary and creates a table with key value pairs (two columns) that I then use with a COALESCE to create dynamic sql for an INSERT statement. This works fine for a single dictionary, but I need to also be able to send up JSON string that contains an array of dictionaries. Right now, my parse function gives me this table variable:

What I need is a table variable like this:

I can get the column names from the first table with this:

SELECT DISTINCT element name from @JSONTable

I should mention that these elementname's can and will change. I will not know the number of distinct elementname values.

UPDATE - Using Umair's answer, I am getting close:

DECLARE @JSONString AS VARCHAR(MAX)

SET @JSONString = '[{"ravid":3,"ravversion":2,"taskid":3},{"ravid":4,"ravversion":7,"taskid":99}]'

IF OBJECT_ID('tempdb..#JSONTable') IS NOT NULL
    DROP TABLE #JSONTable


CREATE TABLE #JSONTable
            (
              elementname VARCHAR(500) ,
              elementvalue VARCHAR(500)
            )
        INSERT  INTO #JSONTable
                ( elementname ,
                  elementvalue

                )
                SELECT  NAME ,
                        StringValue
                FROM    dbo.parseJSON(@JSONString)
                WHERE   LEN(StringValue) > 0 AND NAME IS NOT NULL



--declare a csv variable with all the distinct elements
DECLARE @csv NVARCHAR(max) = STUFF(
    (
         SELECT ',' + elementname
         FROM (
              SELECT DISTINCT elementname
              FROM #JSONTable
         ) AS e
         FOR XML PATH(''), TYPE
    ).value('.', 'nvarchar(max)'),
    1,
    1,
    ''
);

DECLARE @sql NVARCHAR(MAX) = '
    SELECT *
    FROM (
       SELECT *, Row = ROW_NUMBER() OVER (PARTITION BY elementname ORDER BY elementname)
       FROM #JSONTable
    ) AS t
    PIVOT (
        MAX(elementvalue)
        FOR elementname IN (' + @csv + ')
    ) AS p
'

EXEC sp_executesql @sql

But the dictionary values don't correspond to the key. Here is the results of Umair's current answer:

Answer 1

How about

--declare a csv variable with all the distinct elements
DECLARE @csv NVARCHAR(max) = STUFF(
    (
         SELECT ',' + elementname
         FROM (
              SELECT DISTINCT elementname
              FROM #JSONTable
         ) AS e
         FOR XML PATH(''), TYPE
    ).value('.', 'nvarchar(max)'),
    1,
    1,
    ''
);

DECLARE @sql NVARCHAR(MAX) = '
    SELECT *
    FROM (
       SELECT *, Row = ROW_NUMBER() OVER (PARTITION BY elementname ORDER BY elementvalue)
       FROM #JSONTable
    ) AS t
    PIVOT (
        MAX(elementvalue)
        FOR elementname IN (' + @csv + ')
    ) AS p
'

EXEC sp_executesql @sql

ie dynamic pivoting :)

Edit:

Since you do not want to aggregate by anything in the pivot, I added a row number function to assign each distinct elementname a sequentially increasing id (based on element value). This will essentially group the pivot by this row column, producing all the required rows.