SQl Query performace

Question

Post reply

SQl Query performace

Viewing 3 posts - 31 through 32 (of 32 total)

You must be logged in to reply to this topic. Login to reply

abcim SSC Eights! Points: 879 More actions · Answer 1

Thanks to all of repliers,

My problem is mostly solved by your tips and Gail Shaw articles about Indexing.

My query is now only takes longer time for one character searching.

Any tips for further improvement is appreciated.

Just one other question,

If I have three columns A,B,C.

Some times I search with only A, sometimes with only B, sometimes with only C, sometimes with A and B, sometimes with A and C, sometimes with B and C and sometimes A, B and C.

Whether here i use single composite index or single index for A,B and C or something else?

Where to learn more about execution plan?

Gail Shaw SSC Guru Points: 1004504 More actions · Answer 2

abcim (9/25/2010)
Whether here i use single composite index or single index for A,B and C or something else?

Something else. You want the minimum number of indexes that will satisfy all the queries. With the combinations you indicated, I'd go for something like the following indexes:

(A,B,C)

(B,C)

(C,A)

That will allow all the combinations you mentioned to seek on a single index to execute.

Where to learn more about execution plan?

Grant's book.

http://www.sqlservercentral.com/articles/books/65831

Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

We walk in the dark places no others will enter
We stand on the bridge and no one may pass

abcim SSC Eights! Points: 879 More actions · Answer 3

Thank you very much Gail.

I really appreciate your help.