Stock Backtesting - mysql

Question

I'm fairly new to MYSQL but I have experience programming in VBA. I'm trying to create a stored procedure which will backtest a strategy against a table of historical stock price data.The procedure will calculate the 20 Day moving average of closing stock price then if the selected day CLOSE has a price that his higher than the moving average a "buy" is initiated. If a trade is currently on, no new "buys" can be placed and if the selected day CLOSE is below the 20 day moving average a "sell" is initiated. Every time a buy or sell is placed the data is recorded in a table created called backtest results. The data I'm using is from http://finance.yahoo.com/q/hp?s=AAPL+Historical+Prices and I placed it into a table. As you can see the the data is in descending order so in order for me to back test I have to start at the earliest date which happens to be at the bottom. The problem I'm having is that no data is being inputted into this newly created table (Buy Date, Buy Price, Sell Date, Sell Price) . Can anyone spot why this is? Also is mysql suited for row-by-row processing? Thanks!
`Begin
DECLARE total_count int;
DECLARE moving_average decimal;
DECLARE move_up int;
DECLARE current_price decimal;
DECLARE count_var int;
DECLARE buy_price decimal;
DECLARE sell_price decimal;
DECLARE trade_on tinyint;
DECLARE account_balance decimal;
DECLARE start_row int;
DECLARE trade_date date;
SET #trade_on = 0;
SELECT #trade_on;
DROP TABLE IF EXISTS backtestresults;
CREATE TABLE backtestresults (buydate date,buyprice decimal, selldate date, sellprice decimal, accountbalance decimal);
SELECT COUNT(*) INTO #total_count FROM AAPL_Prices;
SELECT * FROM AAPL_Prices WHERE Special_ID = #total_count;
SET #start_row = #total_count -19;
SET #account_balance = 100000;
Loop1: WHILE (start_row > 1) DO
SELECT FORMAT(AVG(SClose),2) FROM AAPL_Prices WHERE Special_ID < #start_row + 19 AND Special_ID > #start_row INTO #moving_average;
SELECT SClose FROM AAPL_Prices WHERE Special_ID = #start_row -19 INTO #current_price;
SELECT TradeDate FROM AAPL_Prices WHERE special_ID = #start_row -19 INTO #trade_date;
IF #trade_on = 0 THEN
IF #current_price > #moving_average THEN
SET #buy_price = #current_price;
SET #trade_on = 1;
SET #account_balance = #account_balance - #buy_price;
INSERT INTO backtestresults (buyprice) values (#buy_price);
INSERT INTO backtestresults (buydate) values (#trade_date);
INSERT INTO backtestresults (balance) values (#account_balance);
End If;
END IF;
IF trade_on = 1 THEN
IF #current_price < #moving_average THEN
SET #sell_price = #current_price;
SET #trade_on = 0;
SET #account_balance = #account_balance + #buy_price;
INSERT INTO backtestresults(sellprice) values (#sell_price);
INSERT INTO backtestresults(selldate) values (#trade_date);
INSERT INTO backtestresults(balance) values (#account_balance);
END IF;
END IF;
SET #start_row = #start_row - 1;
END WHILE Loop1;
SELECT #account_balance;
DESCRIBE backtestresults;
SELECT #start_row;
End`