Consume JSON via OPENJSON and save in table - SQL Server 2016 - json

Question

We recently upgraded our backend DB from SQL Server 2012 to SQL Server 2016 which I realized supports JSON objects. One of our web services return data in the below format, and I am trying to consume it directly using OPENJSON function.
{
"RESULT_1": {
"columns": ["col1", "col2", "col3", "col4"],
"data": [
["0", null, "12345", "other"],
["1", "a", "54321", "MA"],
["0", null, "76543", "RI"]
]
}
}
I want to make sure that I read the column names from the "columns section" and make sure that the correct data is read and pushed in SQL Server 2016.
DECLARE #Json_Array2 nvarchar(max) = '{
"RESULT_1": {
"columns": ["col1", "col2", "col3", "col4"],
"data": [
["0", null, "12345", "other"],
["1", "a", "54321", "MA"],
["0", null, "76543", "RI"]
]
} }';
SELECT [key], value
FROM OPENJSON(#Json_Array2,'$.RESULT_1.columns')
SELECT [key], value
FROM OPENJSON(#Json_Array2,'$.RESULT_1.data')
With above statements, I am able to extract the columns and the data array. Would it be possible to dump this data in a flat table (already existing) with the same column names?
I am able to see all the values of one particular row by:
SELECT [key], value
FROM OPENJSON(#Json_Array2,'$.RESULT_1.data[0]')
key value
0 0
1 NULL
2 12345
3 other
Any pointers are appreciated.
Thank you

Answer 1

If I understand correctly you are trying to extract all elements from the "data" array
Col1 Col2 Col3 Col4
0 NULL 12345 other
1 a 54321 MA
0 NULL 76543 RI
Suppose your Json Structure will not change you can achieve that using the following query:
SET NOCOUNT ON
IF OBJECT_ID ('tempdb..##ToPvt') IS NOT NULL DROP TABLE ##ToPvt
DECLARE #Cmd NVARCHAR(MAX)=''
DECLARE #Table TABLE (Col1 nvarchar(100), Col2 nvarchar(100), Col3 nvarchar(100) , Col4 nvarchar(100))
DECLARE #Json_Array2 nvarchar(max) = '{
"RESULT_1": {
"columns": ["col1", "col2", "col3", "col4"],
"data": [
["0", null, "12345", "other"],
["1", "a", "54321", "MA"],
["0", null, "76543", "RI"]
]
} }';
;WITH Cols ([Key], [Value]) as
(
SELECT [key], value
FROM OPENJSON(#Json_Array2,'$.RESULT_1.columns')
)
, [Rows] as
(
SELECT ROW_NUMBER () OVER (ORDER BY [Key]) Seq, [key], value
FROM OPENJSON(#Json_Array2,'$.RESULT_1.data')
)
,ToPvt as
(
SELECT c.[Key]+1 Cols, x.Value , 'col'+CONVERT(VARCHAR(10),ROW_NUMBER () OVER (PARTITION BY c.Value ORDER BY t.[Key])) Seq
FROM [Rows] t
INNER JOIN Cols C
ON t.[key] = c.[key]
CROSS APPLY OPENJSON(t.value) X
)
SELECT *
INTO ##ToPvt
FROM ToPvt
;WITH Final (Cmd) as
(
SELECT DISTINCT 'SELECT [col1], [col2], [col3],[col4] FROM ##ToPvt
PIVOT
(
MAX([Value]) FOR Seq IN ([col1], [col2], [col3],[col4])
) T
WHERE Cols = '+CONVERT(VARCHAR(10),Cols)+'
;'
FROM ##ToPvt
)
SELECT #Cmd += Cmd
FROM Final
INSERT INTO #Table
EXEC sp_executesql #Cmd
SELECT *
FROM #Table