Skip to content

openjson-transact-sql.md

Latest commit

 

History

History
371 lines (284 loc) · 17.4 KB

openjson-transact-sql.md

File metadata and controls

371 lines (284 loc) · 17.4 KB
title OPENJSON (Transact-SQL) | Microsoft Docs
ms.custom
SQL2016_New_Updated
ms.date 06/10/2016
ms.prod sql-non-specified
ms.reviewer
ms.suite
ms.technology
dbe-json
ms.tgt_pltfrm
ms.topic language-reference
f1_keywords
OPENJSON
OPENJSON_TSQL
helpviewer_keywords
OPENJSON rowset function
JSON, importing
JSON, converting from
ms.assetid 233d0877-046b-4dcc-b5da-adeb22f78531
caps.latest.revision 32
author douglaslMS
ms.author douglasl
manager jhubbard

OPENJSON (Transact-SQL)

[!INCLUDEtsql-appliesto-ss2016-asdb-xxxx-xxx_md]

OPENJSON is a table-value function that parses JSON text and returns objects and properties from the input JSON parameter as rows and columns. OPENJSON provides a rowset view over a JSON document, with the ability to explicitly specify the columns in the rowset and the property paths to use to populate the columns. Since OPENJSON returns a set of rows, you can use OPENJSON function in FROM clause of [!INCLUDEtsql] statements like any other table, view, or table-value function.

Note

The OPENJSON function is available only under compatibility level 130 (or higher). If your database compatibility level is lower than 130, SQL Server will not be able to find and execute OPENJSON function. Other JSON functions are available at all compatibility levels. You can check compatibility level in sys.databases view or in database properties. You can change a compatibility level of database using the following command:
ALTER DATABASE DatabaseName SET COMPATIBILITY_LEVEL = 130

Note that compatibility level 120 might be default even in new Azure SQL Databases.

Use OPENJSON to import JSON data into [!INCLUDEssNoVersion], or to convert JSON data to relational format for an app or service that can't consume JSON directly.

Topic link iconTransact-SQL Syntax Conventions

Syntax


OPENJSON( jsonExpression [ , path ] )  [ <with_clause> ]

<with_clause> ::= WITH ( { colName type [ column_path ] [ AS JSON ] } [ ,...n ] )

Note

column_type must be NVARCHAR(MAX) if AS JSON option is used.

OPENJSON table-value function parses jsonExpression provided as a first argument and returns one or many rows containing data from JSON objects in this expression. jsonExpression might contain nested sub-objects. If user wants to parse sub-object placed on some path within jsonExpression, he can specify second path parameter that will define where is placed JSON sub-object that should be parsed.

openjson

Syntax for OPENJSON TVF

By default, OPENJSON table-value function returns three columns with key name, value, and type of each {key:value} pair that is found in the jsonExpression. As an alternative, user can explicitly specify the schema of the result set that will return OPENJSON function using with_clause:

with_clause

Syntax for WITH clause in OPENJSON TVF

with_clause contains the list of the columns that will be returned by OPENJSON with their types. By default, OPENJSON matches keys in jsonExpression with the column names in with_clause. If column name does not match key name, user can specify optional column_path that represents JSON Path Expression that references some key within the jsonExpression.

Arguments

jsonExpression

Is a Unicode character expression containing the JSON text.

OPENJSON iterates over the elements of the array or the properties of the object in the JSON expression and returns one row for each element or property. The following example returns each property of an object provided as jsonExpression:

DECLARE @json NVARCHAR(4000) = N'{  
  "StringValue":"John",  
  "IntValue":45,  
  "TrueValue":true,  
  "FalseValue":false,  
  "NullValue":null,  
  "ArrayValue":["a","r","r","a","y"],  
  "ObjectValue":{"obj":"ect"}  
}'

SELECT *
FROM OPENJSON(@json)

Results

key value type
StringValue John 1
IntValue Doe 2
TrueValue true 3
FalseValue false 3
NullValue NULL 0
ArrayValue ["a","r","r","a","y"] 4
ObjectValue {"obj":"ect"} 5

path

Is a JSON path expression that references an object or an array within jsonExpression. OPENJSON will seek into JSON text at the specified position and parse only referenced fragment. For more info, see JSON Path Expressions (SQL Server).

The following example returns a nested object by specifying the path:

DECLARE @json NVARCHAR(4000) = N'{  
      "path": {  
            "to":{  
                 "sub-object":["en-GB", "en-UK","de-AT","es-AR","sr-Cyrl"]  
                 }  
              }  
 }';

SELECT [key],value
FROM OPENJSON(@json,'$.path.to."sub-object"')

Results

Key Value
0 en-GB
1 en-UK
2 de-AT
3 es-AR
4 sr-Cyrl

OPENJSON returns indexes of the elements in JSON as keys if JSON array is parsed.

In [!INCLUDEssSQLv14_md] and in [!INCLUDEssSDSfull_md], you can provide a variable as the value of path.

The comparison used to match path steps with the properties of the JSON expression is case-sensitive and collation-unaware (that is, a BIN2 comparison).

with_clause

Explicitly defines output schema that will be returned by OPENJSON function. In the with_clause can be used following elements:

colName
Is the name for the output column.

By default, OPENJSON uses the name of the column to match a property in the JSON text. For example, if you specify the column name in the schema, OPENJSON tries to populate this column with the property "name" in the JSON text.

You can override this default mapping by using the column_path argument.

type
Is the data type for the output column.

column_path
Is the JSON path that specifies the property to return in the specified column. For more info, see the description of the path parameter previously in this topic.

Use column_path to override default mapping rules if the name of an output column doesn't match the name of the property.

For more info, see JSON Path Expressions (SQL Server).

The comparison used to match path steps with the properties of the JSON expression is case-sensitive and collation-unaware (that is, a BIN2 comparison).

AS JSON
Use AS JSON option in column definition to specify that referenced property contains inner object or array. If you don't specify AS JSON for a column, the function returns a scalar value (for example, int, string, true, false) from the specified JSON property on the specified path. If the path represents an object or an array, the function returns null in lax mode or an error in strict mode indicating that the property can't be found at the specified path.
This behavior is similar to the behavior of the JSON_VALUE function.

If you specify AS JSON for a column, the function returns a JSON fragment from the specified JSON property on the specified path. If the path represents a scalar value, the function returns null in lax mode or an error in strict mode indicating that the property can't be found at the specified path. This behavior is similar to the behavior of the JSON_QUERY function.

Note

If you want to return nested JSON fragment from some JSON property, you MUST specify AS JSON flag. Without this option, OPENJSON will return NULL value instead of referenced JSON object or array, or it will return run-time error in strict mode (property cannot be found).

If you specify AS JSON option, the type of the column must be NVARCHAR(MAX).

For example, the following query returns and formats the elements of an array.

DECLARE @json NVARCHAR(MAX) = N'[  
  {  
    "Order": {  
      "Number":"SO43659",  
      "Date":"2011-05-31T00:00:00"  
    },  
    "AccountNumber":"AW29825",  
    "Item": {  
      "Price":2024.9940,  
      "Quantity":1  
    }  
  },  
  {  
    "Order": {  
      "Number":"SO43661",  
      "Date":"2011-06-01T00:00:00"  
    },  
    "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',  
              [Order]  nvarchar(MAX)  AS JSON  
 )

Results

Number Date Customer Quantity Order
SO43659 2011-05-31T00:00:00 AW29825 1 {"Number":"SO43659","Date":"2011-05-31T00:00:00"}
SO43661 2011-06-01T00:00:00 AW73565 3 {"Number":"SO43661", "Date":"2011-06-01T00:00:00"}

Return Value

Columns that will be returned as a result of OPENJSON function depend on WITH option.

  1. When you call OPENJSON with the default schema - that is, when you don't specify an explicit schema in the WITH clause - the function returns a table with the following columns.

  2. Key. An nvarchar(4000) value that contains the name of the specified property or the index of the element in the specified array. The key column has a BIN2 collation.

  3. Value. An nvarchar(max) value that contains the value of the property. The value column inherits its collation from jsonExpression.

  4. Type. An int value that contains the type of the value. The Type column is returned only when you use OPENJSON with the default schema. The type column has one of the following values.

    Value of the Type column JSON data type
    0 null
    1 string
    2 int
    3 true/false
    4 array
    5 object 
 Only first level properties are returned. The statement fails if the JSON text is not properly formatted.
  1. When you call OPENJSON and you specify an explicit schema in the WITH clause, the function returns a table with the schema that you defined in the WITH clause.

Remarks

json_path used in the second argument of OPENJSON or in with_clause might start with lax or strict keyword. In lax mode OPENJSON will not raise any error if object or value on the specified path is not found. OPENJSON will returne either empty result set or NULL value if targeted object cannot be found. In strict mode error will be returned if referenced path cannot be found. If you don't specify mode, OPENJSON parses the root object using lax path mode (that is, as if you had specified the lax option in the path expression).

Some of the examples on this page explicitly specify the path mode, lax or strict. This is optional. If you don't explicitly specify a path mode, lax mode is the default. For more info about path mode and path expressions, see JSON Path Expressions (SQL Server).

Column names in with_clause are matched with the keys in JSON text. If you specify column name [Address.Country] it will be matched with the key "Address.Country". If you need to reference nested key "Country" within the object "Address", you would need to specify the path "$.Address.Country" in column path.

json_path may contain keys with alphanumeric characters. Escape key name in json_path with double quotes if you have some special characters in the keys. As an example, '$."my key $1".regularKey."key with . dot" would match value 1 in the following JSON text:

{
  "my key $1": {
    "regularKey":{
      "key with . dot": 1
    }
  }
}

Examples

Example 1 - Convert a JSON array value to a temporary table

In this example, list of identifiers are provided as JSON array of numbers. Following query converts JSON array to table of identifiers and filters all products with specified ids.

DECLARE @pSearchOptions NVARCHAR(4000) =N'[1,2,3,4]'

SELECT *
FROM products
INNER JOIN OPENJSON(@pSearchOptions) AS productTypes
 ON product.productTypeID=productTypes.value

This query is equivalent to the following example. However, in example below you would need to embed numbers on client side instead of passing them as parameters.

SELECT *
FROM products
WHERE product.productTypeID IN(1,2,3,4)

Example 2 - Merge properties from two JSON objects

The following example selects a union of all the properties of two JSON objects. The two objects have a duplicate "name" property. The example uses the key value to exclude the duplicate row from the results.

DECLARE @json1 NVARCHAR(MAX),@json2 NVARCHAR(MAX)

SET @json1=N'{"name": "John", "surname":"Doe"}'

SET @json2=N'{"name": "John", "age":45}'

SELECT *
FROM OPENJSON(@json1)
UNION ALL
SELECT *
FROM OPENJSON(@json2)
WHERE [key] NOT IN(SELECT [key] FROM OPENJSON(@json1))

Example 3 - Join rows with JSON data stored in table cells using CROSS APPLY

In the following example, the SalesOrderHeader table has a SalesReason text column that contains an array of SalesOrderReasons in JSON format. The SalesOrderReasons objects contain properties like "Quality" and "Manufacturer". The example creates a report that joins every sales order row to the related sales reasons. The OPENJSON operator expands the JSON array of sales reasons as if the reasons were stored in a separate child table. Then the CROSS APPLY operator joins each sales order row to the rows returned by the OPENJSON table-valued function.

SELECT SalesOrderID,OrderDate,value AS Reason
FROM Sales.SalesOrderHeader
CROSS APPLY OPENJSON(SalesReasons)

Tip

When you have to expand JSON arrays stored in individual fields and join them with their parent rows, you typically use the [!INCLUDEtsql] CROSS APPLY operator. For more info about CROSS APPLY, see FROM (Transact-SQL).

The same query can be re-written using OPENJSON with explicitly defined return schema:

SELECT SalesOrderID, OrderDate, value AS Reason  
FROM Sales.SalesOrderHeader  
     CROSS APPLY OPENJSON (SalesReasons) WITH (value nvarchar(100) '$')

In this example, '$' path references each element in arrays. You can use this type of query if you want to explicitly cast returned value.

Example 4 - Combine relational rows and JSON elements with CROSS APPLY

The following query returns the results shown in the following table.

SELECT store.title, location.street, location.lat, location.long  
FROM store  
CROSS APPLY OPENJSON(store.jsonCol, 'lax $.location')   
     WITH (street varchar(500) ,  postcode  varchar(500) '$.postcode' ,  
     lon int '$.geo.longitude', lat int '$.geo.latitude')  
     AS location

Results

title street postcode lon lat
Whole Food Markets 17991 Redmond Way WA 98052 47.666124 -122.10155
Sears 148th Ave NE WA 98052 47.63024 -122.141246,17

Example 5 - Import JSON data into SQL Server

The following example loads an entire JSON object into a [!INCLUDEssNoVersion] table.

DECLARE @json NVARCHAR(max)  = N'{  
  "id" : 2,  
  "firstName": "John",  
  "lastName": "Smith",  
  "isAlive": true,  
  "age": 25,  
  "dateOfBirth": "2015-03-25T12:00:00",  
  "spouse": null  
  }';  
   
  INSERT INTO Person  
  SELECT *   
  FROM OPENJSON(@json)  
  WITH (id int,  
        firstName nvarchar(50), lastName nvarchar(50),   
        isAlive bit, age int,  
        dateOfBirth datetime2, spouse nvarchar(50)

See Also

JSON Path Expressions (SQL Server)
Convert JSON Data to Rows and Columns with OPENJSON (SQL Server)
Use OPENJSON with the Default Schema (SQL Server)
Use OPENJSON with an Explicit Schema (SQL Server)