Subtracting two rows from the same table based on date and hour - sql

Question

I have two tables I would like to join.
Table A
Date | Hour | Direction | Qty
2018-11-20 1 DE/UK 2
2018-11-20 2 DE/UK 6
Table B
Date | Hour | Area | Price
2018-11-20 1 DE 5
2018-11-20 2 DE 4
2018-11-20 1 UK 3
2018-11-20 2 UK 9
I want to join them like this:
Table C
Date | Hour | Direction | Qty | AreaFrom | AreaTo | PriceFrom | PriceTo | Profit
2018-11-20 1 DE/UK 2 DE UK 5 3 3-5 = -2
2018-11-20 2 DE/UK 6 DE UK 4 9 5
I have tried by CROSS Join and other kinds of joins, but have not been able to make it work.
Other related questions I have looked at so far:
SQL subtract two rows based on date and another column
Selecting two rows from the same table

Answer 1

It might not be as complex as Adam makes out. If the TableA had a "directionFrom" and a "directionTo" columns you'd probably have worked this out by yourself. So let's cut up the direction field into two columns:
SELECT
a.[Date], a.[Hour], a.Direction, a.Qty,
f.Area as AreaFrom, t.Area as AreaTo,
f.Price as priceFrom, t.Price as PriceTo,
t.Price-f.Price as profit
FROM
TableA a
INNER JOIN TableB f
ON
a.[Date] = f.[Date] and
a.Hour = b.[Hour] and
LEFT(a.Direction, 2) = f.Area --take the left two as the area from
INNER JOIN TableB t
ON
a.[Date] = t.[Date] and
a.Hour = t.[Hour] and
RIGHT(a.Direction, 2) = t.Area --take the right two as the area to
If you ever have areas with more than two letter codes, you'll have to SUBSTRING on the CHARINDEX of the / instead