Hi,
For reach best performance, its better to put all columns in one index or create one index per column that must have index ?

Farax x - probably neither.
It sounds like you don't know too much about indexes but have heard that having some "speeds things up". it is also true that having some indexes can "slow things down".

I would either read up on indexing in SQL Server, or run all you queries against your database and then run the Database Tuning Advisor to find out what queries are recommended. The former is the better plan, the latter is quick, dirty and cheap but won't give you an optimal set up.

pootle flump ur codings are working excelent.

None of above / both / one of above.

depending upon your table structure , data , NOT NUMBER OF ROWS, relation , dml .

best performance comes with no index in sql-server ( unlinke oracle)
and when needed adding up an index to the column as per required by the query .

but now you have an option of index-referencing in select statement . This gives you a robust option to index your query according to your specification.

thanx alot for your answer

Come again?

He said the best performance comes with no index in sql-server.
Wait...what?

Depends on how you are going to search your data.
If you are going to join or filter on one column at a time, create separate indexes.
If you are usually going to join or filter on multiple columns (often the case if you are using natural keys rather than surrogates), then use a composite index.

...but the nature of those joins and the nature of those filters, as well as the nature of the data, are also considerations on whether or not you index those columns. There is also the whole clustered Vs nonclustered issue.
I think the OP is of too much an uninformed mind to really be able to make much of that advice.

And I couldn't make sense of much mishaalsy said

pootle flump ur codings are working excelent.

Index Intercourse....ummm...intersection!!!

sorry, may be i explain my question badly.I have a table with 10 million records, and i created Separate index for each index-needed columns . my question is :
its better put all columns together in one index or this situation is the best.

Again, it depends. I'm afraid there is no "oh it's best to have them all in one column" or "it's best to have them all in different columns".

Indexing is difficult if you don't know a great deal about it but easy when you do. You would be best to read the BoL entries on indexing and then try asking something more specific.

pootle flump ur codings are working excelent.

can u tell me, when should put several column in one index ?

Want to post the DDL and some sample queries you are using?

Uhm....I already did. Read my post.

OK, besides all the fun and games...

Understand 1 thing

Only the 1st column will make the optimizer decide what index to use

So, putting all the columns in an index, lets say from a phonebook table is useless, if the list of columns are phone_num, Last_name, first_name, ect

AND you were looking up by last name

it would NEVER use that index and would scan...it MIGHT scan the index depending on the number of columns in your select vs. the columns in the table, vs. the columns in the index

So you see....we need to know what the barrel of data is, and how you want to go after it

There's some exotic stuff like merry-go-round scans...but don't think about

The Index Intersection thing however might be beneficial

But you can do some reading

Understanding SQL Server Indexing

SQL Server Index Basics

General Tips on Optimizing SQL Server Indexes

SQL Server Indexes: The Basics - SQLTeam.com