Comparing date ranges

Question

In MySQL, If I have a list of date ranges (range-start and range-end). e.g.

10/06/1983 to 14/06/1983
15/07/1983 to 16/07/1983
18/07/1983 to 18/07/1983
         


        

Answer 1

I created function to deal with this problem in MySQL. Just convert the dates to seconds before use.

DELIMITER ;;

CREATE FUNCTION overlap_interval(x INT,y INT,a INT,b INT)
RETURNS INTEGER DETERMINISTIC
BEGIN
DECLARE
    overlap_amount INTEGER;
    IF (((x <= a) AND (a < y)) OR ((x < b) AND (b <= y)) OR (a < x AND y < b)) THEN
        IF (x < a) THEN
            IF (y < b) THEN
                SET overlap_amount = y - a;
            ELSE
                SET overlap_amount = b - a;
            END IF;
        ELSE
            IF (y < b) THEN
                SET overlap_amount = y - x;
            ELSE
                SET overlap_amount = b - x;
            END IF;
        END IF;
    ELSE
        SET overlap_amount = 0;
    END IF;
    RETURN overlap_amount;
END ;;

DELIMITER ;