Nice Article by the way  I would like to correct some comments in it though

>> A similar process is required for TV, but all operations are conducted 100% in memory <<

That statement is not completly correct.

 FYI :http://support.microsoft.com/default.aspx?scid=kb;en-us;305977

hth

Interesting reading.  Thank you for taking the time to share the ideas.

Good article.

Why do I get an variable declaration error with this statement -

Select * from @tbl INNER JOIN Products p ON @tbl.ItemName = Products.ProductName

Good article, here is an variation that I use ...

Declare
 @SQL   Varchar(200),
  @Array Varchar(200),
  @Tic   Varchar(8),
  @Field Varchar(25)
Set @Array  = ''
--Set @Field  = 'SupplierId'
--Set @Tic    = '' -- for nbrs
Set @Field  = 'ContactName '
Set @Tic    = '''' -- for chars
Select  @Array = @Array + @Tic+ fldName  +@Tic+',' 
 From (Select cast(ContactName as Varchar(50)) as fldName -- enter @field name
   FROM Suppliers WHERE ContactName LIKE 'c%') as s
 Group by fldName
--Print @Array
If len(@Array) > 0
Begin
  Set @Array = left(@Array,len(@Array)-1)
  Set @SQL = 'Select CompanyName from Suppliers where '+@Field+' In ('+@Array+')'
  --print @SQL
  Exec(@SQL)
End

In reply to Remi, here is the full code. I still get an error.

Declare @tbl table (RowId int identity(1,1), ItemName varchar(100))

Insert @tbl
  Select ProductName
   FROM Products
    WHERE ProductName like 'M%'

Select * from @tbl INNER JOIN Products p ON @tbl.ItemName = Products.ProductName

I'd be intereseted to see some actual performance results.  In my mind, it doesn't make sense that a table variable used in this fasion is faster then a cursor.  A table variable adds the over head of having to create the table with an additional column and then select into it before you can even get started.

I do see the value of a table variable in being able to pass it to a store procedure, and the more limited scope and clean up, but I still use temp tables (mainly because it is easier to use the "insert into #mytemp   exec my_sp")

From memory, many cursors (depending on how they are declared) use temp tables to provide the forward/backward functionality anyway.
Also, table variables are not always entirely in memory - they too use tempDB, but have a much more tightly defined scope and so can be managed by SQL more efficiently and may be able to stay in memory - as you've said  

I sometimes still use temp tables in a stored proc when it is a stored proc that returns Iseveral result sets, or performs many calculations, all relying on the one temp table and accessing / joining on several of its columns - it is more efficient to be able to create a clustered index and other indices on the temp table and suffer its recompilation overhead than it is to have slow performing queries using table scans.   I've only made use of it for this reason a couple of times - I usually stick to a table variable and then ALWAYS check out the query plan for anything that is more than a couple of lines (have cut running times from several mins to several seconds by making the switch from variable to temp table)

As an aside, if I need to pass many values (eg an array of ints) to a stored proc from my application, I pass them in a comma-separated varchar(8000) - seems to work a treat.   I have a UDF to parse the string and return a table.  I suppose that XML would also work, but seems a bit too much overhead for such a simple task!

My 2c - cheers!  Ian

PS - nice article - I like the ones that generate plenty of discussion!