Does
SELECT TOP 1000 * FROM TABLE
return the same data execution plan as
SELECT * FROM TABLE?
Please also let me know if this should be moved to ServerFault.
Thanks.
views:
31answers:
1
A:
You can check for yourself. In SSMS, go to Query -> Include Actual Execution Plan
Then run your queries.
e.g. when I run:
SELECT TOP 10 * FROM sys.tables
SELECT * FROM sys.tables
They return different execution plans.
AdaTheDev
2010-06-02 14:05:28
For a single table though (rather than view) I can't imagine it would ever be the case.
Martin Smith
2010-06-02 14:07:50
I am on a time crunch and the queries could run upwards of 8 hours. So I was looking for a way to sort of get around it.
Jim
2010-06-02 14:07:53
@Jim - You can look at estimated query plans as well.
Martin Smith
2010-06-02 14:09:12
@Martin - technically, the execution plan is different for a single table (try it) as it will include a "TOP" operator in the plan. But my main point is, "try it and see with your specific query"
AdaTheDev
2010-06-02 14:13:02
@Ada Good point - Well made!
Martin Smith
2010-06-02 14:14:31
@MartinSmith - I have been doing that as well. I didn't know if there was significant differences between estimated and actual. Thanks.
Jim
2010-06-02 14:17:23