which is more efficent not in(' ',' ') or <>" " and <>" "

[Guest]

I'm trying to make a query more efficient working with large tables. Which
would be the more efficent use?
not in(' ',' ') or
<>" " and <>" "
or possibly another formula or combination...

Thank you,

Wayne Anderson

 

[John Spencer]

It probably doesn't make any difference. The engine that runs the query
will probably optimize them both the same.

 

[Guest]

I agree with John Spencer about it all running the same; however, I like Not
In as it looks cleaner plus easier to add or subtract another item to the
list.

 

[Douglas J. Steele]

It also makes a shorter SQL statement, which can sometimes matter.

 

[Tom Ellison]

Dear Wayne:

In discussing the performance of a query, all issues can be divided into two
classes: those that affect hard drive accesses and those that do not.
Those that do not affect the number of hard drive accesses have very, very
little to do with performance. Those that do have almost everything to do
with performance. This issue does not.

Tom Ellison