Adding array to array with JSON_MODIFY - sql

Question

DECLARE #JSON_CurrentArray NVARCHAR(MAX) = '{"Some List":
[{"Name":"Item1","Id":"2"},{"Name":"Item2","Id":"3"}]}';
DECLARE #JSON_TopLevel NVARCHAR(MAX) = '{"OverAll":[{"Product Section":[]}]}';
SET #JSON_TopLevel = JSON_MODIFY(#JSON_TopLevel, 'append $."Overall"."Product Selection"', JSON_QUERY(#JSON_CurrentArray));
SELECT #JSON_TopLevel;
Ive been trying to stick CurrentArray into TopLevel,
Tried some crazy append/lax/strict combinations... but im new to JSON Manipulation and am almost at 'liquid brain stage' over this item.
I also thought about adding a blank array, but to no avail (i might be doing that wrong also)
Right now im code blind, so, If you can somehow inject one array into another... #foreverindebted.

Answer 1

If I understand you correctly you want something like this:
DECLARE #JSON_CurrentArray NVARCHAR(MAX) = '{"Some List":
[{"Name":"Item1","Id":"2"},{"Name":"Item2","Id":"3"}]}';
DECLARE #JSON_TopLevel NVARCHAR(MAX) = '{"OverAll":[{"Product Section":[]}]}';
SET #JSON_TopLevel = JSON_MODIFY(#JSON_TopLevel, 'append $."OverAll"[0]."Product Section"', JSON_QUERY(#JSON_CurrentArray));
SELECT #JSON_TopLevel;
DBFiddle
Result:
{"OverAll":[{"Product Section":[{"Some List": [{"Name":"Item1","Id":"2"},{"Name":"Item2","Id":"3"}]}]}]}
To check if your path is correct you could use JSON_QUERY and strict mode:
SELECT JSON_QUERY(#JSON_TopLevel, 'strict $."OverAll"."Product Section"')
--Msg 13608 Level 16 State 5 Line 7
--Property cannot be found on the specified JSON path.
-- vs
SELECT JSON_QUERY(#JSON_TopLevel, 'strict $."OverAll"[0]."Product Section"')
-- []