Muokkaa

Jaa

Parse and transform JSON data with OPENJSON

  • Artikkeli

Applies to: SQL Server 2016 (13.x) and later Azure SQL Database Azure SQL Managed Instance Azure Synapse Analytics

The OPENJSON rowset function converts JSON text into a set of rows and columns. After you transform a JSON collection into a rowset with OPENJSON, you can run any SQL query on the returned data or insert it into a SQL Server table. For more information about working with JSON data in the SQL Server Database Engine, see JSON data in SQL Server.

The OPENJSON function takes a single JSON object or a collection of JSON objects and transforms them into one or more rows. By default, the OPENJSON function returns the following data:

  • From a JSON object, the function returns all the key/value pairs that it finds at the first level.
  • From a JSON array, the function returns all the elements of the array with their indexes.

You can add an optional WITH clause to provide a schema that explicitly defines the structure of the output.

OPENJSON with the default output

When you use the OPENJSON function without providing an explicit schema for the results - that is, without a WITH clause after OPENJSON - the function returns a table with the following three columns:

  1. The name of the property in the input object (or the index of the element in the input array).
  2. The value of the property or the array element.
  3. The type (for example, string, number, boolean, array, or object).

OPENJSON returns each property of the JSON object, or each element of the array, as a separate row.

The following example uses OPENJSON with the default schema - that is, without the optional WITH clause - and returns one row for each property of the JSON object.

DECLARE @json NVARCHAR(MAX);

SET @json='{ "name": "John", "surname": "Doe", "age": 45, "skills": [ "SQL", "C#", "MVC" ]}';

SELECT *
FROM OPENJSON(@json);

Here's the result set.

key value type
name John 1
surname Doe 1
age 45 2
skills [ "SQL" ,"C#" ,"MVC" ] 4

For more info and examples, see Use OPENJSON with the Default Schema.

For syntax and usage, see OPENJSON.

OPENJSON output with an explicit structure

When you specify a schema for the results by using the WITH clause of the OPENJSON function, the function returns a table with only the columns that you define in the WITH clause. In the optional WITH clause, you specify a set of output columns, their types, and the paths of the JSON source properties for each output value. OPENJSON iterates through the array of JSON objects, reads the value on the specified path for each column, and converts the value to the specified type.

The following example uses OPENJSON with a schema for the output that you explicitly specify in the WITH clause.

DECLARE @json NVARCHAR(MAX);

SET @json = N'[
    {
        "Order": {
            "Number": "SO43659",
            "Date": "2024-05-31T00:00:00"
        },
        "AccountNumber": "AW29825",
        "Item": {
            "Price": 2024.9940,
            "Quantity": 1
        }
    },
    {
        "Order": {
            "Number": "SO43661",
            "Date": "2024-06-01T00:00:00"
        },
        "AccountNumber": "AW73565",
        "Item": {
            "Price": 2024.9940,
            "Quantity": 3
        }
    }
]';

SELECT *
FROM OPENJSON(@json) WITH (
    Number VARCHAR(200) '$.Order.Number',
    DATE DATETIME '$.Order.Date',
    Customer VARCHAR(200) '$.AccountNumber',
    Quantity INT '$.Item.Quantity'
);

Here's the result set.

Number Date Customer Quantity
SO43659 2024-05-31T00:00:00 AW29825 1
SO43661 2024-06-01T00:00:00 AW73565 3

This function returns and formats the elements of a JSON array.

  • For each element in the JSON array, OPENJSON generates a new row in the output table. The two elements in the JSON array are converted into two rows in the returned table.

  • For each column, specified by using the colName type json_path syntax, OPENJSON converts the value found in each array element on the specified path to the specified type. In this example, values for the Date column are taken from each element on the path $.Order.Date and converted to datetime values.

For more info and examples, see Use OPENJSON with an Explicit Schema (SQL Server).

For syntax and usage, see OPENJSON.

OPENJSON requires compatibility level 130

The OPENJSON function is available only under compatibility level 130 and greater. If your database compatibility level is lower than 130, SQL Server can't find and run the OPENJSON function. Other built-in JSON functions are available at all compatibility levels.

You can check compatibility level in the sys.databases view or in database properties, and change the compatibility level of a database by using the following command:

ALTER DATABASE <DatabaseName> SET COMPATIBILITY_LEVEL = 130;

Related content