Need help to compare pricing using SQL queries Thank you for help in advance.

I have 2 sets of data that show bus journeys and there relevant price from 2 different systems that i need to compare.

Table1
-Brand
-Origin
-Destination
-Price  

Table2
-Brand
-Origin
-Destination
-Price  

So what i need todo is to match all the following fields and return the price from table2 which i have done using the following:

SELECT Table1.Brand ,
       Table1.Origin,  
       Table1.Destination,  
       Table1.Price,  
       Table2.Price 
FROM Table1  
  LEFT JOIN Table2  
         ON Table1.Brand = Table2.Brand  
        AND Table1.Origin = Table2.Origin  
        AND Table1.Destination = Table2.Destination  


ResultTable:  

Brand  |  Origin  |  Destination  |  Price  |  Table2 Price  |


So up to now I have the correct data however i need to the following which i could really do with some help:


Compare Table1.Price against Table2.Price and display the difference in the ResultTable above
Filter out all prices that are the same so all we have left is the different prices
A new query where we compare the Brand, Origin and Destination and if any are missing from table 2 we display those 


Sorry for the long winded explanation but just thought i would try to make it as explicit as possible.
Disclaimer, everything is nullable in your tables so IS NULL predicates may give false positives.

Your query comes a long way, all you need is to add certain predicates:

1 and 2.

SELECT Table1.Brand ,
       Table1.Origin,  
       Table1.Destination,  
       Table1.Price,  
       Table2.Price,
       Table1.Price - Table2.Price as diff 
FROM Table1  
  LEFT JOIN Table2  
         ON Table1.Brand = Table2.Brand  
        AND Table1.Origin = Table2.Origin  
        AND Table1.Destination = Table2.Destination
WHERE Table1.Price - Table2.Price &lt;&gt; 0;   


3 . 

SELECT Table1.Brand ,
       Table1.Origin,  
       Table1.Destination,  
       Table1.Price,  
       Table2.Price,
       Table1.Price - Table2.Price as diff 
FROM Table1  
  LEFT JOIN Table2  
         ON Table1.Brand = Table2.Brand  
        AND Table1.Origin = Table2.Origin  
        AND Table1.Destination = Table2.Destination
WHERE Table2.Price IS NULL;