In the query below, we defined a JSON expression and path. Let’s understand the JSON_VALUE() function using various examples.Įxample 1: Search a key value from JSON string We can specify the lax or strict value in this mode. Path mode: It is an optional argument.JSON_Path: It is the location of a scalar value in the JSON string.It should be a valid expression, and else it returns an error Expression: It is a variable or column containing a JSON string.JSON_MODIFY(): We can modify a value in the JSON Data using this JSON-MODIFY() function.JSON_QUERY: We can extract an array or string from the JSON_QUERY() output.We will explore this function in detail in this article JSON_VALUE(): We can extract a scalar value from the JSON string.ISJSON(): It checks whether we have a valid JSON or not.We have the following JSON functions in SQL Server: You can refer to the following image from Microsoft docs to understand the interoperability between SQL table and JSON. You can go through article category k in SQLShack to understand more details about it. You can also format the T-SQL results in the JSON format. SQL Server provides various built-in-functions to parse, read, transform, and convert JSON objects. It also creates a bridge between a relational database and NoSQL systems. You should know JSON format and work with JSON data in SQL Server. SQL Server 2016 and later supports JSON format data.
It is popular in modern web and mobile applications. JSON is a popular language and many NoSQL databases such a Couchbase, AWS DynamoDB. You can easily interpret JSON formatted data using its key-value pair. If you are familiar with XML, it is a bit hard to understand. It is a lightweight data exchange language. JSON is an acronym for “JavaScript Object Notation”. type.In this article, we will explore JSON_VALUE() function in SQL Server to extract scalar values from JSON data. Because of SQL/JSON path-expression syntax relaxation. Note that if path expression $. were used in Example 19-1 it would give the same result. For the document in Example 4-2 the phone types are "Office" and "Mobile", and the array returned is either or. For each document it returns a VARCHAR2 value whose contents represent a JSON array with elements the phone types, in an unspecified order. The error clause for json_query can specify EMPTY ON ERROR, which means that an empty array ( ) is returned in case of error (no error is raised).Įxample 19-1 shows an example of the use of SQL/JSON function json_query with an array wrapper. The wrapper clause determines the form of the returned string value. Keywords FORMAT JSON are not needed (or available) for json_query - JSON formatting is implicit for the return value. For example, an ASCII TAB character (Unicode character CHARACTER TABULATION, U+0009) is escaped as \t. This includes ensuring that non-ASCII characters in string values are escaped as needed. ( VARCHAR2 is the default.) The value returned always contains well-formed JSON data. A BLOB result is in the A元2UTF8 character set. In the RETURNING clause you can specify data type VARCHAR2, CLOB, or BLOB. The path expression can target any number of JSON values. The second argument to json_query is a SQL/JSON path expression followed by optional clauses RETURNING, WRAPPER, ON ERROR, and ON EMPTY.
The result of evaluating the SQL expression is used as the context item for evaluating the path expression. It can be a table or view column value, a PL/SQL variable, or a bind variable with proper casting. It can be of data type VARCHAR2, CLOB, or BLOB. The first argument to json_query is a SQL expression that returns an instance of a scalar SQL data type (that is, not an object or collection data type).
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