This was the question asked by a Developer when we are investigating a performance loss issues on a database. To the point a derived table means a virtual table that's calculated on the fly from a select statement. By default using derived tables can be tremendously useful in certain situations. In any case if you have 2 queries in hand say one ...

Since the beginning of learning SQL Server I'm pretty much confused with JOIN conditions that defines the way two tables are related in a query by: Specifying the column from each table to be used for the join. A typical join condition specifies a foreign key from one table and its associated key in the other table. Specifying a logical operator ...