GO
CREATE PROCEDURE SPMoveMoney (
    @user_id INT,
    @from_acc INT,
    @to_acc INT,
    @amount MONEY,
    @STATUS INT OUTPUT
) AS
BEGIN
    BEGIN TRANSACTION

    DECLARE @owner_of_acc_from AS INT
    DECLARE @to_exist AS INT
    DECLARE @has_money AS MONEY

    SET @owner_of_acc_from = (
        SELECT COUNT(*) AS 'rows'
        FROM Holder AS H
        INNER JOIN HolderAccount AS HA
            ON H.user_id = HA.user_id
        INNER JOIN Account AS A
            ON HA.acc_nr = A.acc_nr
        WHERE H.user_id = @user_id AND A.acc_nr = @from_acc
    )
    -- no need to make it larger... or w/e
    SET @has_money = (SELECT amount FROM Account WHERE acc_nr = @from_acc)

    SET @to_exist = (SELECT COUNT(*) FROM Account WHERE acc_nr = @to_acc)

    -- User has one account with "from" accountnr
    IF @owner_of_acc_from > 0 BEGIN
        IF @to_exist > 0 BEGIN
            IF @has_money >= @amount BEGIN

                UPDATE Account
                SET amount = amount + @amount
                WHERE acc_nr = @to_acc

                INSERT INTO Log (user_id, from_acc, to_acc, amount, DATE)
                VALUES (@user_id, @from_acc, @to_acc, @amount, GETDATE());

                -- 0: Everything went through
                SET @STATUS = 0
                COMMIT TRANSACTION
            END ELSE BEGIN
                -- 2: From account didn't have enough money
                SET @STATUS = 2
                ROLLBACK TRANSACTION
        END
    END
    END ELSE BEGIN
        -- 1: User id didn't own account or the account didn't exist
        SET @STATUS = 1
        ROLLBACK TRANSACTION
    END
END
GO