mysql histogram function

DELIMITER //
CREATE FUNCTION histogram(col INT, bins INT) RETURNS TABLE (bin_number INT, bin_left INT, bin_right INT, bin_frequency INT)
BEGIN
    DECLARE min, max, bin_size INT;

    SELECT MIN(col) INTO min, MAX(col) INTO max FROM table;
    SET bin_size = (max - min) / bins;

    CREATE TEMPORARY TABLE hist (bin_number INT, bin_left INT, bin_right INT, bin_frequency INT);
    INSERT INTO hist (bin_number, bin_left, bin_right, bin_frequency)
    SELECT FLOOR((col - min) / bin_size) AS bin_number,
           MIN(col) + bin_number * bin_size AS bin_left,
           MIN(col) + (bin_number + 1) * bin_size AS bin_right,
           COUNT(*) AS bin_frequency
    FROM table
    GROUP BY bin_number;

    RETURN SELECT * FROM hist;
END//
DELIMITER ;