12. Rich Wizard, Poor Wizard

DECLARE @SumDifference DECIMAL(8,2)
DECLARE @WizardId INT
DECLARE @WizardDeposit DECIMAL(8,2)
DECLARE @FirstEntry BIT
DECLARE @HostWizard INT
DECLARE @GuestWizard INT
DECLARE @GuestWizardDeposit DECIMAL(8,2)
DECLARE @HostWizardDeposit DECIMAL(8,2)

SET @FirstEntry = 1
SET @SumDifference = 0.00

DECLARE wizardCursor CURSOR FOR
SELECT  w.Id, w.DepositAmount
FROM WizzardDeposits AS w

OPEN wizardCursor
FETCH NEXT FROM wizardCursor INTO @WizardId, @WizardDeposit

WHILE @@FETCH_STATUS = 0
BEGIN


        IF @FirstEntry = 1
        BEGIN
        SET @HostWizard = @WizardId;
        SET @GuestWizard = @WizardId
        SET @GuestWizardDeposit = @WizardDeposit
        SET @FirstEntry = 0
        END
        ELSE
        BEGIN
        SET @HostWizard = @GuestWizard
        SET @GuestWizard = @WizardId

        SET @HostWizardDeposit = @GuestWizardDeposit
        SET @GuestWizardDeposit = @WizardDeposit


        SET @SumDifference +=
        (
            @HostWizardDeposit
            -
            @GuestWizardDeposit
            )
        END

        FETCH NEXT FROM wizardCursor INTO @WizardId, @WizardDeposit

END

CLOSE wizardCursor
DEALLOCATE wizardCursor

SELECT @SumDifference AS 'Sum';