>There is one important problem in this code sample - the OrderDate is not prefixed with the alias. Without that we would need to check which table this column belongs to.
>My rule of thumb - prefix every column with an alias name when the query involves more than 1 table.

I don't disagree with the rule of thumb, especially with several tables. But with 2 tables (a business entity master and a child table of orders), any question about the lineage of OrderDate is more likely a problem with the person in the chair. :)

>
>And of course I wrote about the LEFT JOIN problem several years ago in the following blog post
>

"Of course" ??