Is a JOIN faster than a WHERE?

Question

Suppose I have two tables that are linked (one has a foreign key to the other):

CREATE TABLE Document (
  Id INT PRIMARY KEY,
  Name VARCHAR 255
)

CREATE TAB         


        

Answer 1

I guess that it doesn't make a difference too. To be sure you can check if the explain plan of those two queries is identical. In order to look at the explain plan in MySQL you have to put the "explain" keyword before the statement, eg:

EXPLAIN
SELECT *
FROM Document, DocumentStats
WHERE DocumentStats.Id = Document.Id
  AND DocumentStats.NbViews > 500

I'm sure there exists an equivalent in MSSQL too.

By the way: This looks like this is a 1:1 relationship so I'd just include the nbviews attribute directly in the Document table, therefore you can save a join.