Add JSONArrayLength Function to Return JSON Array Element Count

Why it matters

This function provides a simple way to get the length of a JSON array directly within ClickHouse. It helps users quickly determine the size of JSON array data, improving JSON data processing and validation workflows. If the input is not a valid JSON array, the function returns NULL, ensuring safe handling of invalid JSON strings.

How to use it

Use the JSONArrayLength function by passing a JSON-formatted string representing the array as its argument. It returns an integer count of the outermost array elements or NULL if the JSON is invalid. Example usage:

SELECT JSONArrayLength('[1, 2, 3, 4]');

This will return 4.