So.... you want what? Advice on Training? Solid Quality Learning has some of the best courses I've ever been to.

Books? The "Inside SQL Server" series is a little advanced, but...

Why? It can't possibly be that bad.

I love IT. I'm clean, inside, sitting down, no one is shooting at me, nothing is likely to chew one of my appendages off, I'm well (some would say over)...

This is a bigger topic than the question suggests, but in a nutshell...

You won't be able to manipulate the database of the 3rd party app. Assume that. If it's wrong,...

Since the DATEDIFF was done with 'dd', it's assuming differences in day only. If you're also trying to identify differences in time, which I suspect the Access app deals with...

If you can use identity values, why not use them on the table that you're inserting into?

But, if you can't, you may to look at something like this instead: http://www.sqlmag.com/Article/ArticleID/48165/sql_server_48165.html

If...

When you say "same database" do you also mean on the same server?

This is one well documented approach for performance tuning:

http://www.microsoft.com/technet/prodtechnol/sql/bestpractice/performance_tuning_waits_queues.mspx

Try creating a user defined function that returns your next id and then you can call that function from the select statement.

CREATE Function fn_GetId ()

RETURNS INT

AS

   BEGIN

      ...your code here

  ...

If you can do it that way, then eliminate the temp table and simply batch the request

SELECT SUM()

FROM

   (SELECT...

   UNION

   SELECT...)

GROUP BY WHATEVER

Eliminates the extra overhead of the temp table.

You've got it. To add another table to the join is:

SELECT...

FROM Table1 t1

   INNER JOIN Table2 t2

      ON t1.Key=t2.Key

   INNER JOIN Table3 t3

      ON t2.Key2= t3.key2

The reason you can't simply...

Ball park. As indexes degrade, performance tails off because retreiving the data just requires navigating across more pages. Then, as the statistics are more & more out of date as...

By default there's a button that looks like a scroll with a disk in front of it that is "Generate Change Script." Clicking on that button will show the script...

It's a database mail error.

There isn't a single answer to a question like this. I'd start by looking over the best practices as listed by Microsoft here: http://www.microsoft.com/technet/prodtechnol/sql/bestpractice/default.mspx

Specifically some information on storage: