title: "Format JSON Output Automatically with AUTO Mode (SQL Server) | Microsoft Docs" ms.custom: "" ms.date: "07/17/2017" ms.prod: sql ms.prod_service: "database-engine, sql-database" ms.component: "json" ms.reviewer: "" ms.suite: "sql" ms.technology:
- "dbe-json" ms.tgt_pltfrm: "" ms.topic: conceptual helpviewer_keywords:
- "FOR JSON AUTO" ms.assetid: 178a2a4e-e0f6-49b9-9895-396956d3c7d9 caps.latest.revision: 17 author: "jovanpop-msft" ms.author: "jovanpop" ms.reviewer: douglasl manager: craigg monikerRange: "= azuresqldb-current || >= sql-server-2016 || = sqlallproducts-allversions"
[!INCLUDEappliesto-ss-asdb-xxxx-xxx-md]
To format the output of the FOR JSON clause automatically based on the structure of the SELECT statement, specify the AUTO option.
When you specify the AUTO option, the format of the JSON output is automatically determined based on the order of columns in the SELECT list and their source tables. You can't change this format.
The alternative is to use the PATH option to maintain control over the output.
- For more info about the PATH option, see Format Nested JSON Output with PATH Mode.
- For an overview of both options, see Format Query Results as JSON with FOR JSON.
A query that uses the FOR JSON AUTO option must have a FROM clause.
Here are some examples of the FOR JSON clause with the AUTO option.
Query
When a query references only one table, the results of the FOR JSON AUTO clause are similar to the results of FOR JSON PATH . In this case, FOR JSON AUTO doesn't create nested objects. The only difference is that FOR JSON AUTO outputs dot-separated aliases (for example, Info.MiddleName in the following example) as keys with dots, not as nested objects.
SELECT TOP 5
BusinessEntityID As Id,
FirstName, LastName,
Title As 'Info.Title',
MiddleName As 'Info.MiddleName'
FROM Person.Person
FOR JSON AUTO Result
[{
"Id": 1,
"FirstName": "Ken",
"LastName": "Sánchez",
"Info.MiddleName": "J"
}, {
"Id": 2,
"FirstName": "Terri",
"LastName": "Duffy",
"Info.MiddleName": "Lee"
}, {
"Id": 3,
"FirstName": "Roberto",
"LastName": "Tamburello"
}, {
"Id": 4,
"FirstName": "Rob",
"LastName": "Walters"
}, {
"Id": 5,
"FirstName": "Gail",
"LastName": "Erickson",
"Info.Title": "Ms.",
"Info.MiddleName": "A"
}]Query
When you join tables, columns in the first table are generated as properties of the root object. Columns in the second table are generated as properties of a nested object. The table name or alias of the second table (for example, D in the following example) is used as the name of the nested array.
SELECT TOP 2 SalesOrderNumber,
OrderDate,
UnitPrice,
OrderQty
FROM Sales.SalesOrderHeader H
INNER JOIN Sales.SalesOrderDetail D
ON H.SalesOrderID = D.SalesOrderID
FOR JSON AUTO Result
[{
"SalesOrderNumber": "SO43659",
"OrderDate": "2011-05-31T00:00:00",
"D": [{
"UnitPrice": 24.99,
"OrderQty": 1
}]
}, {
"SalesOrderNumber": "SO43659",
"D": [{
"UnitPrice": 34.40
}, {
"UnitPrice": 134.24,
"OrderQty": 5
}]
}]Query
Instead of using FOR JSON AUTO, you can nest a FOR JSON PATH subquery in the SELECT statement, as shown in the following example. This example outputs the same result as the preceding example.
SELECT TOP 2
SalesOrderNumber,
OrderDate,
(SELECT UnitPrice, OrderQty
FROM Sales.SalesOrderDetail AS D
WHERE H.SalesOrderID = D.SalesOrderID
FOR JSON PATH) AS D
FROM Sales.SalesOrderHeader AS H
FOR JSON PATH Result
[{
"SalesOrderNumber": "SO43659",
"OrderDate": "2011-05-31T00:00:00",
"D": [{
"UnitPrice": 24.99,
"OrderQty": 1
}]
}, {
"SalesOrderNumber": "SO4390",
"D": [{
"UnitPrice": 24.99
}]
}]For specific solutions, use cases, and recommendations, see these blog posts about the built-in JSON support in SQL Server and Azure SQL Database.
For a visual introduction to the built-in JSON support in SQL Server and Azure SQL Database, see the following videos: