Question

I am using SQL Server 2008 and I have a situation where I have view that within my application code I always order by a date contained therein, so I was wondering about efficiency etc.

I came across this blog post SQL Server – Order a View that explains that it is possible to order a view so instead of:

CREATE VIEW v
AS
    SELECT a,b,d FROM t
GO
SELECT a,b,d FROM v ORDER BY d

I could do:

CREATE VIEW v
AS
    SELECT TOP(100) PERCENT a,b,d FROM t ORDER BY d
GO
SELECT a,b,d FROM v

and get the same result.

My question is, which of the above is the more efficient?

If I want it to be as fast as possible would I be better off with the second approach or does it make no difference and sql server will work it all out the same regardless?

Answer 1

complementing Remus answer, if you have a view v like your that contains:

SELECT a,b,d FROM t

once you do

SELECT a,b,d FROM v ORDER BY d

you are actually doing

SELECT a,b,d FROM t ORDER BY d

because a regular (non-indexed) view exists only as s SQL statement on the DB, so once SQL sees select * from view, it replaces with the view definition before generating the execution plan that will be run