Mysql case in trigger not working

Question

I have the following trigger in which CASE statements are not executed:

DELIMITER //
CREATE TRIGGER tri_result AFTER INSERT ON exp_result
FOR EACH ROW BEGIN
    DECLARE priceMinWeekDay FLOAT DEFAULT 0;
    DECLARE priceMinWeekEnd FLOAT DEFAULT 0;
    DECLARE dayOfWeek INT;
    DECLARE limitTop FLOAT;
    DECLARE limitBottom FLOAT;
    DECLARE proccessed INT DEFAULT 0;

    -- Selects the minimum price that appears for this hotel during the last week days (not Saturdays and Sundays) in the last 7 days
    SET priceMinWeekDay = (SELECT MIN(res_price) FROM exp_result JOIN exp_query ON que_id = res_que_id WHERE res_date BETWEEN NOW() - INTERVAL 7 DAY AND NOW() AND res_idHotel = NEW.res_idHotel AND que_day <> 6 AND que_day <> 7);

    -- Selects the minimum price that appears for this hotel during the last Saturdays and Sundays in the last 30 days
    SET priceMinWeekEnd = (SELECT MIN(res_price) FROM exp_result JOIN exp_query ON que_id = res_que_id WHERE res_date BETWEEN NOW() - INTERVAL 30 DAY AND NOW() AND res_idHotel = NEW.res_idHotel AND que_day = 6 OR que_day = 7);

    -- Selects the day of week that has been currently scraped (6 = Saturday, 7 = Sunday)
    SET dayOfWeek = (SELECT que_day FROM exp_query JOIN exp_result ON res_que_id = que_id WHERE res_id = NEW.res_id);

    -- The maximum time a price can be smaller without raising an error
    SET limitBottom = 0.7;

    -- The maximum time a price can be higher without raising an error
    SET limitTop = 1.7;

    -- Set to 0 if 
    SET proccessed = 0;


    -- Price can't be equal or smaller than 0 and bigger than 84000
    IF proccessed = 0 THEN
        IF NEW.res_price <= 0 THEN
            INSERT INTO exp_alert (ale_res_id, ale_proccessed) VALUES (NEW.res_id, 0);
            SET proccessed = 1;
        END IF;
    END IF;
    IF proccessed = 0 THEN
        IF NEW.res_price >= 84000 THEN
            INSERT INTO exp_alert (ale_res_id, ale_proccessed) VALUES (NEW.res_id, 0);
            SET proccessed = 1;
        END IF;
    END IF;

    -- Case to compare week days and weekends between themselves
    CASE
        WHEN dayOfWeek = '6' THEN -- If Saturday
            BEGIN
                IF proccessed = 0 THEN
                    IF (NEW.res_price > limitTop*priceMinWeekEnd) THEN
                        INSERT INTO exp_alert (ale_res_id, ale_proccessed) VALUES (NEW.res_id, 0);
                        SET proccessed = 1;
                    END IF;
                    IF (NEW.res_price < limitBottom*priceMinWeekEnd) THEN
                        INSERT INTO exp_alert (ale_res_id, ale_proccessed) VALUES (NEW.res_id, 0);                          
                        SET proccessed = 1;
                    END IF;
                END IF;
            END;
        WHEN dayOfWeek = '7' THEN -- If Sunday
            BEGIN
                IF proccessed = 0 THEN
                    IF (NEW.res_price > limitTop*priceMinWeekEnd) THEN
                        INSERT INTO exp_alert (ale_res_id, ale_proccessed) VALUES (NEW.res_id, 0);
                        SET proccessed = 1;

                    END IF;
                    IF (NEW.res_price < limitBottom*priceMinWeekEnd) THEN
                        INSERT INTO exp_alert (ale_res_id, ale_proccessed) VALUES (NEW.res_id, 0);
                        SET proccessed = 1;
                    END IF;
                END IF;
            END;
        ELSE -- If weekday (not Saturday and Sunday)
            BEGIN
                IF proccessed = 0 THEN
                    IF (NEW.res_price > limitTop*priceMinWeekDay) THEN
                        INSERT INTO exp_alert (ale_res_id, ale_proccessed) VALUES (NEW.res_id, 0);
                        SET proccessed = 1;
                    END IF;
                    IF (NEW.res_price < limitBottom*priceMinWeekDay) THEN
                        INSERT INTO exp_alert (ale_res_id, ale_proccessed) VALUES (NEW.res_id, 0);
                        SET proccessed = 1;
                    END IF;
                END IF;
            END;
    END CASE;
END;

The table structure is:

Table exp_hotel:

hot_id | hot_webid | hot_name             |hot_starrating | hot_brandbool
7733871| 475       | Richwood Garden Hotel|0              | 0

Table exp_query:

que_id | que_city | que_children | que_adults | que_week | que_day | que_staylength
13     | London   | 0            | 2          | 2        | 6       | 1

Table exp_result:

res_id | res_idHotel | res_rank | res_price | res_userRating | res_oldPrice | res_posa | res_date          | res_que_id
33526  |7733871      |6         |234        |-1              |587           |us.website|2014-03-29 02:30:00|1

Table exp_alert:

ale_id     | ale_res_id | ale_proccessed
(Auto Inc.)

So now if I insert this line in exp_result:

res_id     | res_idHotel | res_rank | res_price | res_userRating | res_oldPrice | res_posa  | res_date          | res_que_id
(Auto Inc.)|7733871      |1         |100        |-1              |587           | us.website|2014-04-24 02:30:00|13

The trigger is perfectly working in the case where NEW.res_price is < 0 or > 84000 when I am setting the res_price to 0 or 84000, but for some reasons it refuses to execute the code which is in all CASE statements when I put a lower price (for instance 100).

I have stored all the variables I use in a test table and all their values are correct (note that either priceMinWeekDay or priceMinWeekEnd is NULL, this is normal).

Answer 1

It is not enough to tell us that is not working, we do not have crystal balls to determine what is your input, what do you expect instead and what is the result. Given the fact that we lack information, the quality of our answers might be not very high, therefore, as I try to help you I can only rely on what I see.

I see that in the case when NEW.res_price < 0 or > 84000, the trigger will execute some inserts and sets proccessed to 1. Later on, you check whether proccessed is 0, which is false, as you have already set proccessed to 1.

If the value is between 0 and 84000, your cases will execute if one of the following criteria is met:

- dayOfWeek is '7' and EW.res_price > limitTop*priceMinWeekEnd
- dayOfWeek is '6' and NEW.res_price <> limitBottom*priceMinWeekEnd
- dayOfWeek differs from '6' and '7' and NEW.res_price <> limitBottom*priceMinWeekEnd