SQL Query to get the Json inside Json values by comma separated - sql

Question

I have the below Json object. I need to get the task names by comma (,) separated.
{
"Model": [
{
"ModelName": "Test Model",
"Object": [
{
"ID": 1,
"Name": "ABC",
"Task" : [
{
TaskID : 1222,
Name: "TaskA"
},
{
TaskID : 154,
Name: "TaskB"
}
]
},
{
"ID": 11,
"Name": "ABCD",
"Task" : [
{
TaskID : 222,
Name: "TaskX"
},
{
TaskID : 234,
Name: "TaskY"
}
]
},
]
}]}
The expected Output should be in the below table. I need the task names should be comma separated.
ModelName ObjectID ObjectName TaskName
Test Model 1 ABC TaskA, TaskB
Test Model 11 ABCD TaskX, TaskY
I tried the below query. But I don't know how to group Task names.
SELECT S1.ModelName,
S2.ID AS ObjectID,
S2.Name AS ObjectName,
S3.TaskName
FROM TableA
CROSS APPLY OPENJSON(JsonData)
WITH (Model NVARCHAR(MAX) '$.Model[0]' AS JSON) S1
CROSS APPLY OPENJSON (S1.Model)
WITH (Object NVARCHAR(MAX) '$.Object' AS JSON,
ID INT '$.ID',
Name NVARCHAR(250) '$.Name') S2
CROSS APPLY OPENJSON (S2.Object)
WITH (Task NVARCHAR(MAX) '$.Task' AS JSON ,
TaskName NVARCHAR(MAX) '$.TaskName') S3

Answer 1

You need to use STRING_AGG() to aggregate the text values and one possible approach (based on the attempt in the question) is the following statement. The aggregation of the task names is for each item in the Object JSON array:
Table:
CREATE TABLE TableA (JsonData varchar(max))
INSERT INTO TableA (JsonData) VALUES ('{
"Model": [
{
"ModelName": "Test Model",
"Object": [
{
"ID": 1,
"Name": "ABC",
"Task" : [
{
"TaskID" : 1222,
"Name": "TaskA"
},
{
"TaskID" : 154,
"Name": "TaskB"
}
]
},
{
"ID": 11,
"Name": "ABCD",
"Task" : [
{
"TaskID" : 222,
"Name": "TaskX"
},
{
"TaskID" : 234,
"Name": "TaskY"
}
]
}
]
}]}')
Statement:
SELECT
j1.ModelName,
j2.ObjectID, j2.ObjectName,
c.TaskName
FROM TableA t
CROSS APPLY OPENJSON(t.JsonData, '$.Model[0]') WITH (
ModelName varchar(50) '$.ModelName',
Object nvarchar(max) '$.Object' AS JSON
) j1
CROSS APPLY OPENJSON(j1.Object, '$') WITH (
ObjectID int '$.ID',
ObjectName varchar(50) '$.Name',
Task nvarchar(max) '$.Task' AS JSON
) j2
CROSS APPLY (
SELECT STRING_AGG([Name], ',') AS TaskName
FROM OPENJSON (j2.Task, '$') WITH (Name varchar(50) '$.Name')
) c

Answer 2

You need to use STRING_AGG() function, which applies to the DB version SQL Server 2017 and later, together with the below GROUP BY expression as
SELECT S1.ModelName, S2.ID AS ObjectID, S2.Name AS ObjectName,
STRING_AGG(S3.TaskName, ',') WITHIN GROUP (ORDER BY TaskName) AS TaskName
FROM <rest of your query>
GROUP BY S1.ModelName, S2.ID, S2.Name
as a complete query :
SELECT S1.ModelName, S3.ObjectID, S3.ObjectName,
STRING_AGG(S4.TaskName, ',') WITHIN GROUP (ORDER BY S4.TaskName) AS TaskName
FROM TableA
CROSS APPLY OPENJSON(JsonData)
WITH (ModelName NVARCHAR(255) '$.Model[0].ModelName') S1
CROSS APPLY OPENJSON (JsonData)
WITH (Object NVARCHAR(MAX) '$.Model[0].Object' AS JSON) S2
CROSS APPLY OPENJSON (S2.Object)
WITH (ObjectID INT '$.ID',
ObjectName NVARCHAR(255) '$.Name',
Task NVARCHAR(MAX) '$.Task' AS JSON) S3
CROSS APPLY OPENJSON (S3.Task)
WITH (TaskID NVARCHAR(MAX) '$.TaskID',
TaskName NVARCHAR(MAX) '$.Name') S4
GROUP BY S1.ModelName, S3.ObjectID, S3.ObjectName
Using WITHIN GROUP (ORDER BY TaskName) is optional, if you do not want ordering, then you can remove that part from the function as in the below demonstration :
Demo