MySQL函数创建神秘错误

Question

create function transfer (account_source int, account_dest int, amount decimal) 
returns BOOLEAN

    BEGIN

    DECLARE currency_source VARCHAR(20);
    DECLARE currency_dest VARCHAR(20);
    DECLARE current_balance DECIMAL;
    DECLARE new_amount DECIMAL;

    select balance into current_balance
    from accounts
    where number = account_source;

    IF amount > current_balance THEN
        return false;
    END IF;

    select currency into currency_source
    from accounts
    where number = account_source;

    select currency into currency_dest
    from accounts
    where number = account_dest;

    IF STRCMP(currency_source,'dollar') = 0 THEN
        IF STRCMP(currency_dest,'euro') = 0 THEN
            set new_amount := amount / 1.23;
        ELSE IF STRCMP(currency_dest,'lbp') = 0 THEN
            set new_amount := amount / 1500;
        END IF;
    end if;

    IF STRCMP(currency_source,'euro') = 0 THEN
        IF STRCMP(currency_dest,'dollar') = 0 THEN
            set new_amount := amount * 1.23;
        ELSE IF STRCMP(currency_dest,'lbp') = 0 THEN
            set new_amount := (amount * 1.23) * 1500;
        END IF;
    end if;

    IF STRCMP(currency_source,'lbp') = 0 THEN
        IF STRCMP(currency_dest,'dollar') = 0 THEN
            set new_amount := amount / 1500;
        ELSE IF STRCMP(currency_dest,'euro') = 0 THEN
            set new_amount := (amount / 1.23) / 1500;
        END IF;
    END IF;

    update accounts
    set balance = balance - amount
    where number = account_source;

    update accounts
    set balance = balance + new_amount
    where number = account_dest;

    return true;

    END;

尝试创建此功能会在第1行给出错误＃1064，所以我无法猜出我所犯的实际错误在哪里。

我创建了＆＃39;撤回＆＃39;在它之前的函数，包含几乎相同的代码并且它起作用，传递函数和撤销函数之间的唯一区别是在开始时声明varchar（20）类型。

任何帮助将不胜感激......