If table Teaching2 is defined as

CREATE TABLE dbo.Teaching2
(
StudentId INT,
InstructorId INT
)

Then how can the (StudentId,CourseId) combination be the candidate key?

EXCELLENT Article!

All I can say is more, more... I want to read more articles like this one!

You can bet I will be sharing this one with...

Could the if statement be simplified to be...

if datediff(dd,dateadd(yy,@age,@dob),@getdate) < 0

set @age = @age - 1

If you have the query...

SELECT .[ID]

, .[Item]

, .[Price]

, .[OrderDate]

, .[Units]

, .[ShipmentDate]

FROM [#Source]

EXCEPT

SELECT [T].[ID]

, [T].[Item]

, [T].[Price]

, [T].[OrderDate]

, [T].[Units]

, [T].[ShipmentDate]

FROM [#Target] [T];

And are thinking about speeding up the query as...

FootyRef (3/25/2014)

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I guess I am not looking at the performance but looking at the results. Why dowe need to do the join when either query produces the same results?

SELECT...

Yes, young Grasshopper. The example doesn't demonstrate the purpose of the article. If new records were inserted into one of the tables, or records deleted from either table,...

In other words, the article shows how to use [font="Courier New"]EXCEPT[/font] to do something really cool. Compare records with matching primary keys to see if they are identical. ...

I have on my clipboard the identical query posted by deroby (I hope I'm pronouncing that correctly.) LEFT OUTER JOIN ... WHERE <somefield> IS NULL is a good step...