Having trouble with MS Sql Server OPENJSON feature - sql-server

Question

I created a sql test script below for this question.
IF OBJECT_ID('tempdb..#temp') IS NOT NULL
DROP TABLE #temp;
CREATE TABLE #temp
(
Id INT NOT NULL PRIMARY KEY
, Attributes NVARCHAR(MAX) NULL
);
INSERT INTO #temp (Id, Attributes)
VALUES (1, '[{"Name":"Step","Value":"A"},{"Name":"State","Value":"Active"}]');
INSERT INTO #temp (Id, Attributes)
VALUES (2, '[{"Name":"Step","Value":"B"},{"Name":"State","Value":"Inactive"}]');
INSERT INTO #temp (Id, Attributes)
VALUES (3, '[{"Name":"State","Value":"Active"}]');
INSERT INTO #temp (Id, Attributes)
VALUES (4, '[{"Name":"Step","Value":"D"}]');
SELECT
t.Id
, t.Attributes
, stepname.Value AS [Step]
, statename.Value AS [State]
FROM #temp t
CROSS APPLY
OPENJSON(t.Attributes)
WITH
(
Name NVARCHAR(MAX) '$.Name'
, Value NVARCHAR(MAX) '$.Value'
) AS stepname
CROSS APPLY
OPENJSON(t.Attributes)
WITH
(
Name NVARCHAR(MAX) '$.Name'
, Value NVARCHAR(MAX) '$.Value'
) AS statename
WHERE 1 = 1
--AND (stepname.Name = statename.Name) -- A
--AND -- B
--( -- B
-- stepname.Name IS NULL -- B
-- OR stepname.Name = 'Step' -- B
--) -- B
--AND -- B
--( -- B
-- statename.Name IS NULL -- B
-- OR statename.Name = 'State' -- B
--); -- B
Running this script as is gives the following output:
Id
Attributes
Step
State
1
[{"Name":"Step","Value":"A"},{"Name":"State","Value":"Active"}]
A
A
1
[{"Name":"Step","Value":"A"},{"Name":"State","Value":"Active"}]
A
Active
1
[{"Name":"Step","Value":"A"},{"Name":"State","Value":"Active"}]
Active
A
1
[{"Name":"Step","Value":"A"},{"Name":"State","Value":"Active"}]
Active
Active
2
[{"Name":"Step","Value":"B"},{"Name":"State","Value":"Inactive"}]
B
B
2
[{"Name":"Step","Value":"B"},{"Name":"State","Value":"Inactive"}]
B
Inactive
2
[{"Name":"Step","Value":"B"},{"Name":"State","Value":"Inactive"}]
Inactive
B
2
[{"Name":"Step","Value":"B"},{"Name":"State","Value":"Inactive"}]
Inactive
Inactive
3
[{"Name":"State","Value":"Active"}]
Active
Active
4
[{"Name":"Step","Value":"D"}]
D
D
What I would like to see in the output though is only 4 rows, one per data row.
Id
Attributes
Step
State
1
[{"Name":"Step","Value":"A"},{"Name":"State","Value":"Active"}]
A
Active
2
[{"Name":"Step","Value":"B"},{"Name":"State","Value":"Inactive"}]
B
Inactive
3
[{"Name":"State","Value":"Active"}]
Active
4
[{"Name":"Step","Value":"D"}]
D
I have left some commented code in my example to see the types of things I've tried but all to no avail. Uncommenting the where statement with a '-- A' gets me closer, but not completely. I thought for sure that uncommenting the statements in the where clause with a '-- B' on the end would give me what I want, but it doesn't. Any ideas on how to do this?
I originally started out with only 1 OPENJSON block but had no success so I thought that perhaps having 2 OPENJSON blocks, one for the Step and one for the State would help, but still not able to get data rows 3 and 4 included since each of those rows is missing one of the 2 JSON values.
Thanks very much for any help!

Answer 1

Conditional aggregation could be used:
SELECT
t.Id
, t.Attributes
, [Step] = MAX(CASE WHEN stepname.Name = 'Step' THEN stepname.Value END)
, [State] = MAX(CASE WHEN statename.Name = 'State' THEN statename.Value END)
FROM #temp t
CROSS APPLY OPENJSON(t.Attributes) WITH (
Name NVARCHAR(MAX) '$.Name'
, Value NVARCHAR(MAX) '$.Value'
) AS stepname
CROSS APPLY OPENJSON(t.Attributes) WITH (
Name NVARCHAR(MAX) '$.Name'
, Value NVARCHAR(MAX) '$.Value'
) AS statename
GROUP BY t.Id, t.Attributes
ORDER BY t.Id;
db<>fiddle demo