id | someDatas | deadline1 | deadline2 | deadline3 | deadline4 | deadline5
---+-----------+-----------+-----------+-----------+-----------+-----------
   |           |           |           |           |           |

id | name
---+-----
   |

id | id_demand | someOthersDatas | id_status
---+-----------+-----------------+----------
   |           |                 |

SELECT dem.*, st.`name` as 'statusName'
FROM `status` st
INNER JOIN `events` eve
    ON eve.id_status = st.id
INNER JOIN `demand` dem
    ON eve.id_demand = dem.id
WHERE st.`name` IN ('A', 'B', 'C', 'D')
    AND eve.id IN
    (
        SELECT MAX(even.id) ev
        FROM `demand` de
        INNER JOIN `events` even
            ON even.id_demand = de.id
        GROUP BY de.id
    );

DROP TEMPORARY TABLE IF EXISTS pendingDemands;
CREATE TEMPORARY TABLE IF NOT EXISTS pendingDemands
SELECT /* the query shown above */

delimiter //

CREATE FUNCTION `easter_f`(X INTEGER) RETURNS date
BEGIN
    DECLARE K,M,S,A,D,R,OG,SZ,OE,OS INT;
    DECLARE EASTERDATE DATE;
    SET K = X DIV 100;
    SET M = 15 + (3*K + 3) DIV 4 - (8*K + 13) DIV 25;
    SET S = 2 - (3*K + 3) DIV 4;
    SET A = X MOD 19;
    SET D = (19*A + M) MOD 30;
    SET R = (D + A DIV 11) DIV 29;
    SET OG = 21 + D - R ;
    SET SZ = 7 - (X + X DIV 4 + S) MOD 7;
    SET OE = 7 - (OG - SZ) MOD 7;
    SET OS = OG + OE;
    SET EASTERDATE = date_add(concat(X, '-03-01'), INTERVAL OS-1 DAY);
RETURN EASTERDATE;
END//

DROP TEMPORARY TABLE IF EXISTS days_off;
CREATE TEMPORARY TABLE IF NOT EXISTS days_off
(
    date_off VARCHAR(5)
);

INSERT INTO days_off VALUES('01-01'),
                           ('05-01'),
                           ('05-08'),
                           ('07-14'),
                           ('08-15'),
                           ('11-01'),
                           ('11-11'),
                           ('12-25');

delimiter //
DROP FUNCTION IF EXISTS `isDayOff`;
CREATE FUNCTION `isDayOff`(d DATETIME) RETURNS BOOL
BEGIN
    SET @monthDay = (SELECT DATE_FORMAT(d, '%m-%d'));
    SET @easter = (SELECT easter_f(YEAR(d)));
    SET @dayWeek = (SELECT DAYOFWEEK(d));
    SET @result = if (@dayWeek = 1
                        OR @dayWeek = 7
                        OR (SELECT COUNT(*) FROM days_off WHERE date_off = @monthDay) > 0
                        OR DATE_ADD(@easter, INTERVAL 1 DAY) = d
                        OR DATE_ADD(@easter, INTERVAL 40 DAY) = d
                        OR DATE_ADD(@easter, INTERVAL 50 DAY) = d,
                    TRUE,
                    FALSE);
    RETURN (@result);
END//

DELIMITER //
DROP FUNCTION IF EXISTS `get_next_valid_date`;
CREATE FUNCTION `get_next_valid_date`(MyDate DATETIME) RETURNS DATETIME
BEGIN
    REPEAT
        SET MyDate = (DATE_ADD(MyDate, INTERVAL 1 DAY));
        SET @someCondition = (select isDayOff(MyDate));
    UNTIL (@someCondition = 0) END REPEAT;
    RETURN MyDate;
END//