If statement with multiple statements inside loops doesn't work - mysql

Question

I have the follow procedure :
DELIMITER $$
CREATE PROCEDURE getCost(
in p_idp int(11),
out p_cost double)
BEGIN
DECLARE strt double;
DECLARE stop double;
DECLARE diff double;
DECLARE p_hs INTEGER;
DECLARE p_hf INTEGER;
DECLARE p_hcost double;
DECLARE v_finished INTEGER DEFAULT 0;
DECLARE i INTEGER;
-- declare cursor
DECLARE tariffe_cursor CURSOR FOR
SELECT hs,hf,cost FROM tariffe ORDER BY hs;
-- declare NOT FOUND handler
DECLARE CONTINUE HANDLER
FOR NOT FOUND SET v_finished = 1;
SELECT UNIX_TIMESTAMP(data_inizio) INTO strt
FROM prenotazioni WHERE IdP = p_idp;
SET stop = UNIX_TIMESTAMP();
SET diff = stop - strt;
SET diff = diff / 3600;
SET i = 0;
SET p_cost = 0;
WHILE i < diff
DO
OPEN tariffe_cursor;
get_tariffe: LOOP
FETCH next FROM tariffe_cursor INTO p_hs,p_hf,p_hcost;
IF v_finished = 1 THEN
LEAVE get_tariffe;
END IF;
IF (i >= p_hs AND i < p_hf) THEN
SET p_cost = p_cost + p_hcost;
SET v_finished = 1;
END IF;
END LOOP get_tariffe;
CLOSE tariffe_cursor;
SET i = i + 1;
END WHILE;
IF diff < 0.25 THEN
SET p_cost = 0;
END IF;
END$$
DELIMITER ;
Table tariffe has 2 records:
hs = 0, hf = 3, hcost = 3
hs = 3, hf = 1000, hcost = 2
Suppose DIFF = 1.50 -> Expect p_cost to be 6
Suppose DIFF = 3.75 -> Expect p_cost to be 11
but p_cost is always 3
Tried to use some INSERTs (into a temp table) to check the WHILE loop and the cursor loop and realized that the
IF (i >= p_hs AND i < p_hf) THEN
is computed true only when i = 0 (first while loop) but when i > 0 is always computed as false.
F.ex. when i = 1 the first cursor FETCH returns hs=0,hf=3,hcost=3, but IF seems to be false
What I'm doing wrong?
I've also tried (with no success)
IF (i >= p_hs) AND (i < p_hf)
IF i >= p_hs AND i < p_hf
LOGIC:
Diff is the number of hours between start and stop (renting period).
Tariffe Table contains rental cost: from 0 to 3 hours -> 3 euros, from 3 upto 1000 -> 2 euros.
While loop iterates for every single hour of rental
Cursor loop check for the right hourly cost and add it to p_cost

Answer 1

The problem is that you never set v_finished back to 0 when you leave the get_tariffe loop and continue the while i < diff loop. So on subsequent iterations, if v_finished = 1 is always true and you leave the loop before adding to p_cost.
Put
SET v_vinished = 0;
after
OPEN tariffe_cursor;
But I don't think you'll ever get 11 as a result. You do SET v_finished = 1; after adding the first p_hcost, so it will never process the second row of the table. I'm not sure what your intended logic is to get 11. Maybe you should just take out the line that sets v_finished.