Assistance with a SQL query parsing JSON - sql

Question

I have a database table called QueueItems that contains the following fields:
SpecificData contains JSON data so we have used the well known parseJSON SQL function that is about on the internet.
So an example of the JSON is below:
{"DynamicProperties":{"IdentificationIndex":"CK","PaymentMethod":"C","Variants1":"010 ZERO BAL,716 ZERO BAL,717 ZERO BAL","Variants2":"CHECK_010,CHECK_716,CHECK_717","CustomerCode":"NO","FreeSelectionField":"NO","FreeSelectionValue":"NO","Variants1Line":"RFFOAVIS","Variants2Line":"ZRFFOUS_C","VendorFrom":"1","VendorTo":"999999999","DueDateCheck":"Yes","PaymentMethodSel":"Yes","PaymentMethodSelOnFail":"No","LineItemsOfPayDocs":"Yes","StartImmediately":"Yes","CreatePaymentMedium":"No","ExportFormat":"HTML Format","ExcludeValues":"Yes"}}
When I run the SQL function parseJSON it returns me the data in this format:
Now, the query I am trying to write is:
SELECT QueueItemID, QueueItemStatus, StartProcessing, EndProcessing, [THEN append each column from parseJSON but this needs to be transposed first]
So far I have managed to transpose the JSON into columns with a single row using:
DECLARE
#Cols AS VARCHAR(MAX) = ''
,#Query AS NVARCHAR(MAX) = ''
,#ParamDef AS NVARCHAR(MAX)
,#Json AS VARCHAR(MAX) = '{"DynamicProperties":{"IdentificationIndex":"CK","PaymentMethod":"C","Variants1":"010 ZERO BAL,716 ZERO BAL,717 ZERO BAL","Variants2":"CHECK_010,CHECK_716,CHECK_717","CustomerCode":"NO","FreeSelectionField":"NO","FreeSelectionValue":"NO","Variants1Line":"RFFOAVIS","Variants2Line":"ZRFFOUS_C","VendorFrom":"1","VendorTo":"999999999","DueDateCheck":"Yes","PaymentMethodSel":"Yes","PaymentMethodSelOnFail":"No","LineItemsOfPayDocs":"Yes","StartImmediately":"Yes","CreatePaymentMedium":"No","ExportFormat":"HTML Format","ExcludeValues":"Yes"}}'
SELECT
#Cols += ',' + Name
FROM
parseJson(#Json)
WHERE
Name NOT IN ('DynamicProperties', '-')
SET #Cols = SUBSTRING(#Cols,2,LEN(#Cols))
SET #Query = N'SELECT *
FROM
(
SELECT [StringValue], [Name]
FROM parseJson(''' + #Json + ''')
) [d]
PIVOT
(
MAX([StringValue])
FOR [Name] IN (' + #Cols + ')
) [piv]'
EXECUTE (#Query)
As you can see the JSON may contain ANY data, so I am dynamically inserting the column names into the PIVOT statement FOR IN.
Now to Join this data as additional columns onto my main query SELECT QueueItemId.. FROM QueueItems I was originally going to put this code in a UDF and call it as part of my main query / stored procedure but I have two issues:
1) The sp_executesql or EXEC statement - not allowed in a UDF
2) To return a table from a UDF I need to define the fields... The fields are dynamic... I could get this working by passing back XML to my stored procedure but I still have issue number 1.
So the question is:
1) Is there any better way or writing this then using a UDF?
2) Is there any other way or transposing the output from parseJSON?
3) Is there any other way of using the PIVOT but not having to specify the columns?
Any help would be much appreciated.
EDIT IN RESPONSE TO M ALI
I know the syntax is wrong and it doesn't work but the query would look something like this:
DECLARE #Cols AS VARCHAR(MAX) = ''
,#Query AS NVARCHAR(MAX) = ''
SELECT
QI.QueueItemID,
QI.QueueItemStatus,
QI.StartProcessing,
QI.EndProcessing,
SD.*
FROM QueueItems AS QI
LEFT JOIN
(
SELECT
#Cols += ',' + Name
FROM
parseJson(QI.SpecificData)
WHERE
Name NOT IN ('DynamicProperties', '-')
SET #Cols = SUBSTRING(#Cols,2,LEN(#Cols))
SET #Query = N'SELECT *
FROM
(
SELECT [StringValue], [Name]
FROM parseJson(''' + QI.SpecificData + ''')
) [d]
PIVOT
(
MAX([StringValue])
FOR [Name] IN (' + #Cols + ')
) [piv]'
EXECUTE (#Query)
) AS SD
And the results would be the columns from QueueItems, joined on the left by columns from the parsed JSON string.
QueueItemID, StartProcessing, EndProcessing, IndentificationIndex, PaymentMethod etc...