Querying XML in SQL Server - json

Question

I'm a newbie to SQL Server. I have a table Accounts which is defined as:
OrganizationId int,
AccountDetails varchar(max)
The AccountDetails column contains XML data.
The data in the table looks like this:
1 | <Account><Id>100</Id><Name>A</Name></Account>
2 | <Account><Id>200</Id><Name>B</Name></Account>
3 | <Account><Id>300</Id><Name>C</Name></Account>
4 | <Account><Id>400</Id><Name>D</Name></Account>
I need write a SQL query to get the records from this table where AccountId is 200 or 400.
The query should return two rows (#2 and #4) in JSON format, like this:
result1 : { "account_id": 200, "account_name": B }
result2 : { "account_id": 400, "account_name": D }
I'm wondering how do I go about this?
Thank you.
For # 1 above, should I be trying to cast the AccountDetails column to XML type and then use "nodes" feature for querying/filtering?
For #2, I should be writing a SQL function to convert the XML to JSON first and querying XML to build the JSON as needed?

Answer 1

As already mentioned, it is much better to use a proper XML data type for the AccountDetails column.
Please try the following solution.
It will work starting from SQL Server 2016 onwards.
SQL
-- DDL and sample data population, start
DECLARE #tbl TABLE (OrganizationId INT IDENTITY PRIMARY KEY, AccountDetails NVARCHAR(MAX));
INSERT #tbl (AccountDetails) VALUES
('<Account><Id>100</Id><Name>A</Name></Account>'),
('<Account><Id>200</Id><Name>B</Name></Account>'),
('<Account><Id>300</Id><Name>C</Name></Account>'),
('<Account><Id>400</Id><Name>D</Name></Account>');
-- DDL and sample data population, end
;WITH rs AS
(
SELECT t.OrganizationId
, account_id = x.value('(/Account/Id/text())[1]', 'INT')
, account_name = x.value('(/Account/Name/text())[1]', 'VARCHAR(20)')
FROM #tbl AS t
CROSS APPLY (VALUES(TRY_CAST(AccountDetails AS XML))) AS t1(x)
)
SELECT *
, JSONData = (SELECT rs.account_id, rs.account_name FOR JSON PATH,WITHOUT_ARRAY_WRAPPER)
FROM rs
WHERE rs.account_id IN (200, 400);
Output
OrganizationId
account_id
account_name
JSONData
2
200
B
{"account_id":200,"account_name":"B"}
4
400
D
{"account_id":400,"account_name":"D"}