There is a function called isjson to verify if a given column is a valid json document. In the next query we will extract the element lastname from the column jsoncol, in the where clause we validate if the value of jsoncol column is a valid json document using isjson. If you want to access a sub-element of the json document, you can use the function jsonvalue. c:\tools>db.exe export -map c:\MySampleMap.xml -out c:\data\customers.json -connstr "Data Source=localhost Initial Catalog=Northwind Integrated Security=SSPI "Ĭustomers. MS-SQL Server can store json documents in nvarchar columns. Customer joined with Orders by CustomerID key, Orders Joined with Employee by EmployeeID key. We can also use the ‘’ argument to get the whole JSON string. It is an optional argument, so we do not get any error. You can also provide a second (optional) argument to specify the object or array to extract. When we use the FOR JSON clause in the SELECT statement, we can specify the structure of the output explicitly, or let the structure of the SELECT statement determine the output.
To use this function, you provide the JSON expression as an argument. The data from the MSSQL can be exported to JSON by adding the FOR JSON clause into a SELECT statement. Precisa de Consultoria em SQL Server 25 July 2015 3 Database Query Development Data Formatting and Validation Little Known Features Hacks Integrations JSON.
We can retrieve the whole JSON document by removing the second argument. When using JSON with SQL Server, you can use the JSONQUERY () function to extract an object or an array from a JSON string.
In below example we are doing 3 nested levels for demo purpose. SELECT JSONQUERY(data, '.employees 0') AS 'Result' It retrieves the first JSON object and gives you the following output.
MSSQL JSON QUERY HOW TO
Lets say you want to export customer data along with orders they placed as nested JSON document then we have to supply Map file so JSON Generator can figure out how to JOIN two datasets and how to Shape JSON.
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