MYSQL - function not returning expected results - mysql

Question

I'm building a site for property rentals. I'm doing the search bit now and I'm trying to setup a function I can call for each property. The function needs to grab all rows from the rental_periods table attached to a given property then work out the best (cheapest) weekly price.
I have the following tables setup already.
properties - One line for each property
rental_periods - Multiple lines for each property, tied with id.
Each line is selfcatered or catered.
If selfcatered the price needs to be worked out from prices given in:
WeekDayPerDay - wdpd
WeekEndPerNight - wepn
Monthly price - monthly
Week price - wk
If catered the prices can be given in:
PerPersonPerNight - pppn
PerNight - pn
PerPersonPerWeek - pppw
I need a function that takes a property id and then grabs all periods that apply, then depending on selfcatered/catered works out the price per week that's best.
What I've got so far doesn't seem to be working. It either returns NULL or returns 100000.00 (my upper limit default price).
Here's the code
DELIMITER $$
CREATE FUNCTION get_price(myid INT)
RETURNS VARCHAR(20)
BEGIN
DECLARE done INT DEFAULT 0;
DECLARE price decimal(30,3) default 100000.000;
DECLARE id INT;
DECLARE prop_id INT;
DECLARE type enum('catered','selfcatered');
DECLARE name varchar(45);
DECLARE `from` date;
DECLARE `to` date;
DECLARE currency varchar(45);
DECLARE so tinyint;
DECLARE wk decimal(30,3);
DECLARE wepn decimal(30,3);
DECLARE wdpd decimal(30,3);
DECLARE monthly decimal(30,3);
DECLARE extra decimal(30,3);
DECLARE pppn decimal(30,3);
DECLARE pn decimal(30,3);
DECLARE pppw decimal(30,3);
DECLARE minstay int;
DECLARE maxstay int;
DECLARE breakfast varchar(45);
DECLARE annual TINYINT;
DECLARE cur1 CURSOR FOR SELECT * FROM rental_periods WHERE prop_id = myid;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;
OPEN cur1;
REPEAT
FETCH cur1 INTO id, prop_id, type, name, `from`, `to`, currency, so, wk, wepn, wdpd, minstay, maxstay, monthly, extra, pppn, pn, pppw, breakfast, annual;
IF NOT done THEN
IF (#type = "selfcatered") THEN
IF (#wdpd > 0 AND (#wdpd * 7) < #price) THEN
SET price = #wdpd * 7;
END IF;
IF (#wepn > 0 AND (#wepn * 7) < #price) THEN
SET price = #wepn * 7;
END IF;
IF ((#wdpd > 0 AND #wepn > 0) AND
(#wdpd * 5 + #wepn * 2) < #price) THEN
SET price = #wdpd * 5 + #wepn * 2;
END IF;
IF (#monthly > 0 AND (#monthly / (52 / 12)) < #price) THEN
SET price = #monthly / (52 / 12);
END IF;
IF (#wk > 0 AND #wk < #price) THEN
SET price = #wk;
END IF;
ELSE
IF (#pppn > 0 AND (#pppn * 7) < #price) THEN
SET price = #pppn * 7;
END IF;
IF (#pn > 0 AND (#pn * 7) < #price) THEN
SET price = #pn * 7;
END IF;
IF (#pppw > 0 AND (#pppw) < #price) THEN
SET price = #pppw;
END IF;
END IF;
END IF;
UNTIL done END REPEAT;
CLOSE cur1;
RETURN price;
END $$
i'm hoping/not thats it's something stupid with how I've arranged it, or my lack of pure MySQL.
ANY help would be very helpful.
EDIT:
Here's an example row from rental_periods:
INSERT INTO `rental_periods` (`id`, `prop_id`, `type`, `name`, `from`, `to`, `currency`, `so`, `wk`, `wepn`, `wdpd`, `minstay`, `maxstay`, `monthly`, `extra`, `pppn`, `pn`, `pppw`, `breakfast`, `annual`)
VALUES (64732, 32, 'selfcatered', 'Summer', '2012-06-01', '2012-08-31', NULL, 1, '350', '60', '100', '', '', '', '', NULL, NULL, NULL, NULL, 0);
I'd expect the function to return 350 picked from the per week column. However if the wepn was 30, not 60, I'd expect 210 to come back (worked out from 7 * wepn prices).
The code im testing in SP:
DELIMITER $$
CREATE procedure tmp_get_price(myid INT)
BEGIN
DECLARE done INT DEFAULT 0;
DECLARE price decimal(30,3) default 100000.000;
DECLARE id INT;
DECLARE prop_id INT;
DECLARE type enum('catered','selfcatered');
DECLARE name varchar(45);
DECLARE `from` date;
DECLARE `to` date;
DECLARE currency varchar(45);
DECLARE so tinyint;
DECLARE wk decimal(30,3);
DECLARE wepn decimal(30,3);
DECLARE wdpd decimal(30,3);
DECLARE monthly decimal(30,3);
DECLARE extra decimal(30,3);
DECLARE pppn decimal(30,3);
DECLARE pn decimal(30,3);
DECLARE pppw decimal(30,3);
DECLARE minstay int;
DECLARE maxstay int;
DECLARE breakfast varchar(45);
DECLARE annual TINYINT;
DECLARE cur1 CURSOR FOR SELECT id, prop_id, type, name, `from`, `to`, currency, so, wk, wepn, wdpd, minstay, maxstay, monthly, extra, pppn, pn, pppw, breakfast, annual FROM rental_periods WHERE prop_id = myid;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;
OPEN cur1;
REPEAT
FETCH cur1 INTO id, prop_id, type, name, `from`, `to`, currency, so, wk, wepn, wdpd, minstay, maxstay, monthly, extra, pppn, pn, pppw, breakfast, annual;
IF NOT done THEN
IF (type = "selfcatered") THEN
IF (wdpd > 0 AND (wdpd * 7) < price) THEN
SET price = wdpd * 7;
END IF;
IF (wepn > 0 AND (wepn * 7) < price) THEN
SET price = wepn * 7;
END IF;
IF ((wdpd > 0 AND wepn > 0) AND
(wdpd * 5 + wepn * 2) < price) THEN
SET price = wdpd * 5 + wepn * 2;
END IF;
IF (monthly > 0 AND (monthly / (52 / 12)) < price) THEN
SET price = monthly / (52 / 12);
END IF;
IF (wk > 0 AND wk < price) THEN
SET price = wk;
END IF;
ELSE
IF (pppn > 0 AND (pppn * 7) < price) THEN
SET price = pppn * 7;
END IF;
IF (pn > 0 AND (pn * 7) < price) THEN
SET price = pn * 7;
END IF;
IF (pppw > 0 AND (pppw) < price) THEN
SET price = pppw;
END IF;
END IF;
END IF;
UNTIL done END REPEAT;
CLOSE cur1;
select price;
END $$
still doesnt work... :( am i being stupid... cant see why this wont work..?!?
gets the periods...
goes throught each one...
if the price is less set it....
select price....?!?
if i put multiple selects in... for example inside the cursor.
only the very bottom one fires and returns 100000.000
i've setup all the value fields as decimals and not allowing NULL...
any thoughts when im going wrong...? also tried debug by inserting in to log table... never fires..?!

Answer 1

Need to read more on cursors this seams a good place to start...
http://www.kbedell.com/2009/03/02/a-simple-example-of-a-mysql-stored-procedure-that-uses-a-cursor/