Excluding rows from second table but including in comparison - sql

Question

I have two tables with the same data in it I need to compare one column here is the ddl for testing
USE [DifferencesDB]
GO
/****** Object: Table [dbo].[FirstTable] Script Date: 11/06/2019 15:27:22 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [dbo].[FirstTable](
[Id] [int] NULL,
[Column1] [nchar](10) NULL,
[Column2] [nchar](10) NULL,
[Column4] [decimal](18, 0) NULL
) ON [PRIMARY]
GO
INSERT [dbo].[FirstTable] ([Id], [Column1], [Column2], [Column4]) VALUES (1, N'test ', N'test ', 30)
GO
INSERT [dbo].[FirstTable] ([Id], [Column1], [Column2], [Column4]) VALUES (2, N'test2 ', N'test3 ', 18)
GO
CREATE TABLE [dbo].[SecondTable](
[Id] [int] NULL,
[Column1] [nchar](10) NULL,
[Column2] [nchar](10) NULL,
[Column4] [decimal](18, 5) NULL
) ON [PRIMARY]
GO
INSERT [dbo].[SecondTable] ([Id], [Column1], [Column2], [Column4]) VALUES (1, N'test ', N'test ', 13.56895)
GO
INSERT [dbo].[SecondTable] ([Id], [Column1], [Column2], [Column4]) VALUES (2, N'test2 ', N'test3 ', 18.456 )
GO
As you can see here what I want to do is compare to the two tables and the Data in Column 4 which is a decimal.
/****** Script for SelectTopNRows command from SSMS ******/
SELECT ABS(T0.Column4 -T1.Column4) as 'Difference'
FROM [FirstTable] T0, [SecondTable] T1
where T0.Id =T1.ID
This works but it gives me back tones of extra rows this gets me the difference I require so how do I exclude the rows from the other table.
So, for example, it should say the difference is I would like the data to be returned from the second table but also the difference column as well.
.456
Edit
TO show what is happening on live data.
Please see my new query here
SELECT GoodData_Lines.Qty,
Invalid_Lines.Qty,
abs(GoodData_Lines.Qty- Invalid_Lines.Qty) AS 'Difference'
FROM GoodData_Lines
left OUTER JOIN Invalid_MCSSOPLines
ON GoodData_Lines.LineID = Invalid_Lines.LineID

Answer 1

Not exactly sure what the question was, but based on how I understand it, will this do?
SELECT T1.*, ABS(T0.Column4 -T1.Column4) as 'Difference'
FROM [FirstTable] T0 right join [SecondTable] T1
on T0.Id =T1.ID

Answer 2

This can be a solution?
[EDIT] following your update
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [dbo].[GoodData_Lines](
[LineID] [int] NULL,
[Column1] [nchar](10) NULL,
[Column2] [nchar](10) NULL,
[Qty] [decimal](18, 0) NULL
) ON [PRIMARY]
GO
INSERT [dbo].[GoodData_Lines] ([LineID], [Column1], [Column2], [Qty]) VALUES (1, N'test ', N'test ', 30)
GO
INSERT [dbo].[GoodData_Lines] ([LineID], [Column1], [Column2], [Qty]) VALUES (2, N'test2 ', N'test3 ', 18)
GO
CREATE TABLE [dbo].[Invalid_MCSSOPLines](
[LineID] [int] NULL,
[Column1] [nchar](10) NULL,
[Column2] [nchar](10) NULL,
[Qty] [decimal](18, 5) NULL
) ON [PRIMARY]
GO
INSERT [dbo].[Invalid_MCSSOPLines] ([LineID], [Column1], [Column2], [Qty]) VALUES (1, N'test ', N'test ', 13.56895)
GO
INSERT [dbo].[Invalid_MCSSOPLines] ([LineID], [Column1], [Column2], [Qty]) VALUES (2, N'test2 ', N'test3 ', 18.456 )
GO
SELECT GoodData_Lines.Qty,
isnull( [Invalid_MCSSOPLines].Qty,0) invalid_qty,
abs(GoodData_Lines.Qty - isnull([Invalid_MCSSOPLines].Qty,0)) AS 'Difference'
FROM GoodData_Lines
left OUTER JOIN Invalid_MCSSOPLines
ON GoodData_Lines.LineID = [Invalid_MCSSOPLines].LineID
-- eventually drop table if no more needed
-- DROP TABLE [GoodData_Lines]
-- DROP TABLE [Invalid_MCSSOPLines]