SQL Query optimization - sql

Question

I have some questions about my query. I call this store-procedure in my first page, so it is important for me if it is optimize enough.
I do some select with some basic where expression, Then I filter them with some expression I passed through this store-procedure.
It is also considerable for me to select top n and its gonna search through millions of items (but I have hundreds of items already) and then do some paging in my website.
Select top (#NumberOfRows)
...
from(
SELECT
row_number() OVER (ORDER BY tblEventOpen.TicketAt, tblEvent.EventName, tblEventDetail.TimeStart) as RowNumber
, ...
FROM --[...some inner join logic...]
WHERE
(tblEventOpen.isValid = 1) AND (tblEvent.isValid = 1) and
(tblCondition_ResellerDetail.ResellerID = 1) AND
(tblEventOpen.TicketAt >= GETDATE()) AND
(GETDATE() BETWEEN
DATEADD(minute, (tblEventDetail.TimeStart - 60 * tblCondition_ResellerDetail.StartTime) , tblEventOpen.TicketAt)
AND DATEADD(minute, (tblEventDetail.TimeStart - 60 * tblCondition_ResellerDetail.EndTime) , tblEventOpen.TicketAt))
) as t1
where RowNumber >= (#PageNumber -1) * #NumberOfRows and
(#city='' or #city is null or city like #city) and
(#At is null or #At=At) and
(#TimeStartInMinute=-1 or #TimeStartInMinute=TimeStartInMinute) and
(#EventName='' or EventName like #EventName) and
(#CategoryID=-1 or #CategoryID = CategoryID) and
(#EventID is null or #EventID = EventID) and
(#DetailID is null or #DetailID = DetailID)
ORDER BY RowNumber
I'm worry about this part:
(GETDATE() BETWEEN
DATEADD(minute, (tblEventDetail.TimeStart - 60 * tblCondition_ResellerDetail.StartTime) , tblEventOpen.TicketAt)
AND DATEADD(minute, (tblEventDetail.TimeStart - 60 * tblCondition_ResellerDetail.EndTime) , tblEventOpen.TicketAt))
How does table t1 execute? I mean after I put some where expression after t1 (line 17 and further), does it filter items after execution of t1? for example I filter result by rownumber of 10, so it mean the inner (...) as t1 select will only return 10 items, or it select all items then my outer select will take 10 of them?
I want to filter my result by some optional parameters, so I put something like #DetailID is null or #DetailID = DetailID, is it a good way?
Anything else should I consider to make it faster (more optimize)?

Answer 1

My comment on your query:
You're correct, you should worry about condition "GETDATE() BETWEEN ...". Comparing value with function involving more than 1 table will most likely scan entire search space. Simplify your condition or if possible add a computed column for such function
Put all conditions except "RowNumber >= ..." in inner query
Its okay to put optional condition the way you do. I do it too :-)
Make sure you have index at least one for each column employed in the where clause as the first column of the index, and then the primary key. It would be better if your primary key is clustered
Well, these are based on my own experience. It may or may be not applicable to your situation.
[UPDATE] Here's the complete query
Select top (#NumberOfRows)
...
from(
SELECT
row_number() OVER (ORDER BY tblEventOpen.TicketAt, tblEvent.EventName, tblEventDetail.TimeStart) as RowNumber
, ...
FROM --[...some inner join logic...]
WHERE
(tblEventOpen.isValid = 1) AND (tblEvent.isValid = 1) and
(tblCondition_ResellerDetail.ResellerID = 1) AND
(tblEventOpen.TicketAt >= GETDATE()) AND
(GETDATE() BETWEEN
DATEADD(minute, (tblEventDetail.TimeStart - 60 * tblCondition_ResellerDetail.StartTime) , tblEventOpen.TicketAt)
AND DATEADD(minute, (tblEventDetail.TimeStart - 60 * tblCondition_ResellerDetail.EndTime) , tblEventOpen.TicketAt)) and
(#city='' or #city is null or city like #city) and
(#At is null or #At=At) and
(#TimeStartInMinute=-1 or #TimeStartInMinute=TimeStartInMinute) and
(#EventName='' or EventName like #EventName) and
(#CategoryID=-1 or #CategoryID = CategoryID) and
(#EventID is null or #EventID = EventID) and
(#DetailID is null or #DetailID = DetailID)
) as t1
where RowNumber >= (#PageNumber -1) * #NumberOfRows
ORDER BY RowNumber

Answer 2

Whilst you can seek advice on your query, it is better to learn how to optimise it yourself.
You need to view the execution plan, identify the bottlenecks and then see if there is anything that can be done to make an improvement.
In SSMS you can click "Query" ---> "Include Actual Execution Plan" before you run your query. (Ctrl+M) is they keyboard shortcut.
Then execute your query. SSMS will create a new tab in the results pane. Which will show you how the SQL engine executes your query, you can hover over each node for more information. The cost % will be particularly interesting, allowing you to see the most expensive part of your query.
It's difficult to advise you any more without that execution plan, which is why a number of people commented on your question. Your schema and indexes change how the query is executed, so it's not something that someone can accuratly replicate in their own environment without scripts for tables / indexes etc.... Even then statistics could be out of date and other problems could arise.
You can also execute SET STATISTICS PROFILE ON to get a textual view of the plan (maybe useful to seek help).
There are a number of articles that can help you fix the bottlenecks, or post another question for more advice.
http://msdn.microsoft.com/en-us/library/ms178071.aspx
SQL Server Query Plan Analysis
Execution Plan Basics