Read Nested Json through sql query - json

Question

Currently I have this piece of code
DECLARE #json NVARCHAR(MAX)
SET #json =
N'[
{
"objOrg": {
"EmpIds": [
{
"Id": 101
},
{
"Id": 102
},
{
"Id": 103
}
]
}
}
]'
How can I return EmpId values pivoted such as
Id1
Id2
Id3
101
102
103

Answer 1

OPENJSON without a schema will return the array index. Then pass the inner object to OPENJSON again to parse it out, and pivot the final result using PIVOT or MAX(CASE
DECLARE #json nvarchar(max) =
N'[
{
"objOrg": {
"EmpIds": [
{
"Id": 101
},
{
"Id": 102
},
{
"Id": 103
}
]
}
}
]';
SELECT MAX(CASE WHEN arr.[key] = 0 THEN ID END) AS Id1,
MAX(CASE WHEN arr.[key] = 1 THEN ID END) AS Id2,
MAX(CASE WHEN arr.[key] = 2 THEN ID END) AS Id3
FROM OPENJSON(#json, '$[0].objOrg.EmpIds') arr
CROSS APPLY OPENJSON (arr.value)
WITH (
Id int
) AS j;
-- alternatively
SELECT p.*
FROM (
SELECT arr.[key] + 1 AS [key], j.Id
FROM OPENJSON(#json, '$[0].objOrg.EmpIds') arr
CROSS APPLY OPENJSON (arr.value)
WITH (
Id int
) AS j
) j
PIVOT (
MAX(j.Id) FOR j.[key] IN
([1], [2], [3])
) p;
db<>fiddle

Answer 2

You can use OPENJSON() along with ROW_NUMBER() window function such as
DECLARE
#json AS NVARCHAR(MAX),
#query AS NVARCHAR(MAX);
SET #json =
N'[
{
"objOrg": {
"EmpIds": [
{
"Id": 101
},
{
"Id": 102
},
{
"Id": 103
}
]
}
}
]';
SELECT j.*, ROW_NUMBER() OVER (ORDER BY j.Id) AS rn
INTO t_json
FROM OPENJSON(#json)
WITH (
JS NVARCHAR(MAX) '$.objOrg.EmpIds' AS JSON
) AS j0
CROSS APPLY OPENJSON (j0.JS)
WITH (
Id INT '$.Id'
) AS j;
SET #query = CONCAT('SELECT',
STUFF(
(SELECT CONCAT(', MAX(CASE WHEN rn=' , CAST(rn AS VARCHAR) , ' THEN Id END) AS Id', CAST(rn AS VARCHAR))
FROM t_json
ORDER BY rn
FOR XML PATH(''), type).value('.', 'NVARCHAR(MAX)'),
1,1,''
),' FROM t_json');
EXECUTE(#query)
Demo