SQL Server - Uso de sentencia IF en bucle WHILE -SQL Server

WHILE (@SumaYardas <= @consumoTelaTotal)

	BEGIN

	--WITH

	SELECT @SumaYardas = @SumaYardas + SALDO_YD FROM #TBL WHERE Fila = @Idfila;

	SELECT @NOROLLO = NO_ROLLO from #TBL where Fila = @Idfila; 

	UPDATE TBL_INV_TELA SET PROGRAMADO = 1 where NO_ROLLO = @NOROLLO;

	UPDATE TBL_INV_TELA SET SALDO_YD = 0.00 WHERE NO_ROLLO = @NOROLLO;

	IF (@SumaYardas >= @consumoTelaTotal)

		BEGIN

			SELECT @RESTA1 = @SumaYardas - SALDO_YD FROM #TBL WHERE Fila = @Idfila-1;

			SELECT @RESTA2 = @consumoTelaTotal - @RESTA1;

			SELECT @RESTA3 = SALDO_YD FROM #TBL WHERE Fila = @Idfila - @RESTA2;

			UPDATE TBL_INV_TELA SET SALDO_YD = @RESTA3 WHERE NO_ROLLO = @NOROLLO;

		END

	SET @Idfila = @Idfila + 1;

	END