Reading JSON structure from the database (SQL Server) - json

Question

I'm using a SQL Server database. I have a table which has a field that stores the following JSON file structure:
{
"Internal":[
{
"GUID":"7c2fc2b3-7ae2-42c5-b6f0-13137f58348c",
"Type":1,
"ID":155
},
{
"GUID":"8774cbcb-e594-4c64-8ecb-b71d4f97cea4",
"Type":2,
"Link":134
}
],
"External":[
{
"GUID":"be41536b-33ea-4e12-8a11-544aa15c1edb",
"Type":2,
"Link":174
},
{
"GUID":"49383921-5bd8-4cf9-a104-67f957b7fdc7",
"Type":1,
"Link":202
}
]
}
My problem is finding the GUID value. How do I find the value of Link (202), if I know that the GUID I'm looking for is 49383921-5bd8-4cf9-a104-67f957b7fdc7?
I know the solution is to use the CROSS APPLY but I can't come to a solution. I looked through a few threads in the forum, but after a few hours I still can't get the correct query, so I am posting my question on the forum.
Here is my initial query which selects a JSON structure from the database:
SELECT m.Formulardata -- here is a JSON structure
FROM [dbo].[Vorgaenge] v
LEFT JOIN [dbo].[Vorgangsschritte] s ON v.id = s.Vorgang_ID
LEFT JOIN [dbo].[Vorgangsmassnahmen] m ON s.id = m.Vorgangsschritt_ID
WHERE m.Vorgangsmassnahme_ID = 21 AND v.id = #Vorgang_ID

Answer 1

Please try the following solution.
SQL #1 is a minimal reproducible example.
SQL #2 is close as much as possible to your environment.
SQL #1
-- DDL and sample data population, start
DECLARE #tbl TABLE (ID INT IDENTITY PRIMARY KEY, Formulardata NVARCHAR(MAX));
INSERT INTO #tbl (Formulardata) VALUES
(N'{
"Internal":[
{
"GUID":"7c2fc2b3-7ae2-42c5-b6f0-13137f58348c",
"Type":1,
"ID":155
},
{
"GUID":"8774cbcb-e594-4c64-8ecb-b71d4f97cea4",
"Type":2,
"Link":134
}
],
"External":[
{
"GUID":"be41536b-33ea-4e12-8a11-544aa15c1edb",
"Type":2,
"Link":174
},
{
"GUID":"49383921-5bd8-4cf9-a104-67f957b7fdc7",
"Type":1,
"Link":202
}
]
}');
-- DDL and sample data population, end
SELECT ID, u.*
FROM #tbl
CROSS APPLY OPENJSON(Formulardata) x
CROSS APPLY OPENJSON(x.Value)
WITH
(
GUID UNIQUEIDENTIFIER '$.GUID',
Type INT '$.Type',
Link INT '$.Link'
) AS u
-- WHERE u.Link = 202;
SQL #2
;WITH rs AS
(
SELECT m.Formulardata -- here is a JSON structure
FROM [dbo].[Vorgaenge] v
LEFT JOIN [dbo].[Vorgangsschritte] s ON v.id = s.Vorgang_ID
LEFT JOIN [dbo].[Vorgangsmassnahmen] m ON s.id = m.Vorgangsschritt_ID
WHERE m.Vorgangsmassnahme_ID = 21 AND v.id = #Vorgang_ID
)
SELECT ID, u.*
FROM rs
CROSS APPLY OPENJSON(Formulardata) x
CROSS APPLY OPENJSON(x.Value)
WITH
(
GUID UNIQUEIDENTIFIER '$.GUID',
Type INT '$.Type',
Link INT '$.Link'
) AS u
WHERE u.Link = 202;
Output
+----+--------------------------------------+------+------+
| ID | GUID | Type | Link |
+----+--------------------------------------+------+------+
| 1 | 7c2fc2b3-7ae2-42c5-b6f0-13137f58348c | 1 | NULL |
| 1 | 8774cbcb-e594-4c64-8ecb-b71d4f97cea4 | 2 | 134 |
| 1 | be41536b-33ea-4e12-8a11-544aa15c1edb | 2 | 174 |
| 1 | 49383921-5bd8-4cf9-a104-67f957b7fdc7 | 1 | 202 |
+----+--------------------------------------+------+------+

Answer 2

I do not have access right now ot a server that I could test it on, but if you know that it is in the 'external' branch then I think that this should work:
SELECT x.Link
FROM [dbo].[Vorgaenge] v
LEFT JOIN [dbo].[Vorgangsschritte] s ON v.id = s.Vorgang_ID
LEFT JOIN [dbo].[Vorgangsmassnahmen] m ON s.id = m.Vorgangsschritt_ID
CROSS APPLY OPENJSON(m.Formulardata)
WITH (
Internal NVARCHAR(MAX) '$.Internal' AS JSON,
Externals NVARCHAR(MAX) '$.External' AS JSON
) AS a
OUTER APPLY OPENJSON(a.Externals)
WITH (
Guid NVARCHAR(MAX) '$.GUID',
Type INT '$.Type',
Link INT '$.Link'
) AS x
WHERE m.Vorgangsmassnahme_ID = 21 AND v.id = #Vorgang_ID
AND ISJSON(m.Formulardata) > 0
AND x.Type = 2
AND x.GUID = '49383921-5bd8-4cf9-a104-67f957b7fdc7'