SQL OPENJSON Array in Objects - sql

Question

I have a table with the following structure/rows:
ID
OptionName
OptionValue
0
Gender
Male
1
Gender
Female
I want to query the database and return the following JSON:
[{
"OptionName":"Gender",
"Values":[
"Male",
"Female"
]
}]
However the result I'm currently getting is this:
[{
"OptionName":"Gender",
"Values":[
{
"OptionValue":"Male"
},
{
"OptionValue":"Female"
}
]
}]
Here is my Query:
SELECT TOP(1) OptionName,
(
JSON_QUERY(
(
SELECT OptionValue
FROM [TestJSON].[dbo].[Options]
WHERE OptionName = 'Gender'
FOR JSON PATH
)
)
) AS [Values]
FROM [TestJSON].[dbo].[Options]
WHERE OptionName = 'Gender'
FOR JSON PATH
What can I do to get the result I need?

Answer 1

Although SQL Server 2022 introduced JSON_ARRAY() function, it's difficult to use it to build a JSON array with variable items count, so you may try a string based approach:
SELECT DISTINCT o.OptionName, JSON_QUERY(a.[Values]) AS [Values]
FROM Options o
CROSS APPLY (
SELECT CONCAT('[', STRING_AGG(CONCAT('"', OptionValue, '"'), ','), ']')
FROM Options
WHERE OptionName = o.OptionName
) a ([Values])
--WHERE o.OptionName = 'Gender'
FOR JSON PATH
If you know the maximum number of values for each option (5 in the example), a combination of JSON_ARRAY() and PIVOT relational operator is another option:
SELECT OptionName, JSON_ARRAY([1], [2], [3], [4], [5]) AS [Values]
FROM (
SELECT OptionName, OptionValue, ROW_NUMBER() OVER (PARTITION BY OptionName ORDER BY ID) AS Rn
FROM Options
) t
PIVOT (MAX(OptionValue) FOR Rn IN ([1], [2], [3], [4], [5])) p
FOR JSON PATH