Rediger

Del via

Format JSON output automatically with AUTO mode

Applies to: SQL Server 2016 (13.x) and later versions Azure SQL Database Azure SQL Managed Instance Azure Synapse Analytics (serverless SQL pool only) SQL analytics endpoint in Microsoft Fabric Warehouse in Microsoft Fabric SQL database in Microsoft Fabric

To automatically format the output of the FOR JSON clause 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.

Use the PATH option if you want to control the output.

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.

Note

The MSSQL extension for Visual Studio Code can auto-format the JSON results (as seen in this article) instead of displaying an unformatted string.

Examples

The code samples in this article use the AdventureWorks2025 or AdventureWorksDW2025 sample database, which you can download from the Microsoft SQL Server Samples and Community Projects home page.

A. Format JSON from a single table

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;

Here's the result set.

[{
    "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"
}]

B. Format JSON for joined tables

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 AS H
     INNER JOIN Sales.SalesOrderDetail AS D
         ON H.SalesOrderID = D.SalesOrderID
FOR JSON AUTO;

Here's the result set.

[{
    "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
    }]
}]

C. Use FOR JSON PATH to match AUTO output

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;

Here's the result set.

[{
    "SalesOrderNumber": "SO43659",
    "OrderDate": "2011-05-31T00:00:00",
    "D": [{
        "UnitPrice": 24.99,
        "OrderQty": 1
    }]
}, {
    "SalesOrderNumber": "SO4390",
    "D": [{
        "UnitPrice": 24.99
    }]
}]

Learn more about JSON in the SQL Database Engine

For a visual introduction to the built-in JSON support, see JSON as a bridge between NoSQL and relational worlds.

Related content

  • Last updated on