PostgreSQL – JSON_ARRAY_LENGTH Function
The json_array_length function is used to determine the number of elements in a JSON array. It’s particularly useful when you’re working with JSON data and need to find out how many items are present in an array within a JSON document.
The syntax for using the json_array_length function is as follows:
json_array_length(json_array)Here’s an example of how you might use the json_array_length function:
SELECT json_array_length('[1, 2, 3, 4, 5]'::json);In this example, the function would return 5 because there are five elements in the JSON array [1, 2, 3, 4, 5].
You can also use the json_array_length function in combination with other queries to filter rows based on the length of JSON arrays in a column. For instance, you could find all rows where the JSON array has a certain length:
SELECT * FROM your_table WHERE json_array_length(json_column) = 3;This would retrieve all rows where the JSON array within the json_column has a length of 3.