I pity any already confused developer who reads this article. As, despite the title, it isn't about sub-queries. What the author refers to are called Derived Tables, Table Expressions (which is where Common Table Expressions get their name from) or sometimes (almost equally confusingly) Inline Views. Any clues - the execution plan has no SEMI-JOIN in it. Refer to Chapter 6 "Subqueries, Expressions and Ranking Functions" of the IBG SS2008 T-SQL Querying book for reference.

Sorry to be negative, but one of Paul Randall's top myths busted is "sub-queries are always slower". And, this kind of confusing article just adds to the myth.

But, if it was titled Table Expressions vs Joins :exclamation: