Add range to an array with JSON_MODIFY - sql

Question

I am trying to add an array to another array using JSON_MODIFY.
The situation is, I have an array kind stored json data in database. It looks like this:
declare #base nvarchar(max) = '[{"name":"base"}]';
And I am getting another set of data which is also in the shape of array:
declare #test1 nvarchar(max) = '[{"name":"test1"},{"name":"example1"}]';
I am trying to use JSON_MODIFY and JSON_QUERY magics to append them together but it gives me unexpected results.
declare #base nvarchar(max) = '[{"name":"base"}]';
declare #test1 nvarchar(max) = '[{"name":"test1"},{"name":"example1"}]';
set #base = JSON_MODIFY(#base,'append $',JSON_QUERY(#test1));
select #base;
Output:
[{"name":"base"}, [{"name":"test1"},{"name":"example1"}]]
But what I want is using those methods to make it work like kind of Add-Range:
[{"name":"base"},{"name":"test1"},{"name":"example1"}]
I am kind of lost on this process and I don't know where to look at for this kind of functionality.
I will use this from a C# service to directly modify through the code. That's why I cannot use Store procedures and functions as well.
Edit #1:
With regarding to reply from #Salman A, i appreciate your answer but the thing is, as i said earlier, it is a little bit difficult to use on my query running through code. Which is:
declare #test1 nvarchar(max) = '[{"name":"test1"},{"name":"example1"}]';
UPDATE dbo.ExampleTable
SET [Data] = JSON_MODIFY([Data], 'append $', JSON_QUERY(#test1))
WHERE [UniqueId] = 'some_guid_here'
I have tried it to adapt the answer that i like this :
declare #test1 nvarchar(max) = '[{"name":"test1"},{"name":"example1"}]';
UPDATE dbo.ExampleTable
SET [Data] = (
select [Data] = JSON_MODIFY([Data],'append $',item)
from OPENJSON(#test1)
with ([item] nvarchar(max) '$' as JSON)
)
WHERE [UniqueId] = 'some_id'
Actually, it works if #test1 only have 1 item, but in case of having more than 1 item in #test1, it gives the error:
Subquery returned more than 1 value. This is not permitted when the subquery follows = .....
What is the logical way to use this in a update set subquery

Answer 1

You can use OPENJSON to convert the array to rows and append items one by one:
declare #base nvarchar(max) = '[{"name":"base"}]';
declare #test1 nvarchar(max) = '[{"name":"test1"},{"name":"example1"}]';
select #base = json_modify(#base, 'append $', item)
from openjson(#test1)
with ([item] nvarchar(max) '$' as json);
select #base;
Returns:
[{"name":"base"},{"name":"test1"},{"name":"example1"}]
Revised answer for update query
If you're using SQL Server 2017+ then a reasonably safe solution is to concatenate the array using STRING_AGG but build individual rows using JSON functions. It is relatively easy to use this idea in an update query:
DECLARE #base NVARCHAR(MAX) = '[{"name":"base"}]';
DECLARE #test NVARCHAR(MAX) = '[{"foo":"bar"},{"baz":"meh"}]';
SELECT '[' + STRING_AGG(jsonstr, ',') WITHIN GROUP (ORDER BY pos) + ']'
FROM (
SELECT value, 1000 + [key] FROM OPENJSON(#base)
UNION ALL
SELECT value, 2000 + [key] FROM OPENJSON(#test)
) AS x(jsonstr, pos);
Alternately, you can use a recursive CTE that calls JSON_MODIFY multiple times to build the JSON; you can use the result in update query:
CREATE TABLE t(
id INT NOT NULL PRIMARY KEY IDENTITY,
data NVARCHAR(MAX)
);
INSERT INTO t(data) VALUES
('[{"name":"1.1"}]'),
('[{"name":"2.1"},{"name":"2.2"}]');
WITH rows(data, pos) AS (
SELECT value, [key]
FROM OPENJSON('[{"foo":"bar"},{"baz":"meh"}]')
), rcte(id, data, pos) AS (
SELECT id, data, -1
FROM t
UNION ALL
SELECT prev.id, JSON_MODIFY(prev.data, 'append $', JSON_QUERY(curr.data)), prev.pos + 1
FROM rcte AS prev
JOIN rows AS curr ON curr.pos = prev.pos + 1
)
UPDATE t
SET data = (
SELECT TOP 1 data
FROM rcte
WHERE id = t.id
ORDER BY pos DESC
);
Demo on db<>fiddle