What Transact-SQL function verifies if a piece of text is valid JSON?

The function that verifies if a piece of text is valid JSON is ISJSON. This function checks whether the provided input string is in a valid JSON format, returning 1 if it is valid and 0 if it is not. This distinction is crucial when working with JSON data in databases, as it allows developers and data engineers to validate input before performing further operations, ensuring data integrity and preventing errors during processing.

In contrast, the other functions serve different purposes: JSON_QUERY allows you to extract JSON objects or arrays from a JSON string, JSON_VALUE enables you to extract a scalar value from a JSON string, and VAL_JSON is not a standard function found in Transact-SQL for JSON validation. Understanding these functions and their specific use cases is essential for effective data manipulation and querying in environments that utilize JSON data.