Index question

I have the following index:
CREATE UNIQUE INDEX [MYINDEX1] ON [dbo].[LOGIN_TABLE]([Loginid],
logindate]) ON [PRIMARY]
GO
Do I still need to create the following index ?
CREATE INDEX [MYINDEX2] ON [dbo].[LOGIN_TABLE]([Loginid]) ON [PRIMARY]
GO
Thanks for any feedback........
DXC,
SQL Server stores statistics for the more left column in the key. This index
could be used for logic expressions referencing [Loginid] or ([Loginid] and
[logindate]). If you create the second index, may be SQL Server can decide to
use it because the key is shorter than the first one, so more rows can fit in
a page and less IO operations will be required.
Try some "select" statements with just the first index. If you are ok with
the response time and execution plan selected by SQL Server then do not
create the second one. Remember, indexes help sql server to find the data
faster, but also put more load for insert, delete, and update operations.
AMB
"DXC" wrote:

> I have the following index:
> CREATE UNIQUE INDEX [MYINDEX1] ON [dbo].[LOGIN_TABLE]([Loginid],
> logindate]) ON [PRIMARY]
> GO
> Do I still need to create the following index ?
>
> CREATE INDEX [MYINDEX2] ON [dbo].[LOGIN_TABLE]([Loginid]) ON [PRIMARY]
> GO
>
> Thanks for any feedback........
|||No. MYINDEX2 is redundant. SQL Server can use MYINDEX1 if it needs to seek
on Loginid
"DXC" <DXC@.discussions.microsoft.com> wrote in message
news:34A7F75B-5178-4DD1-BD31-AFEE69C13458@.microsoft.com...
>I have the following index:
> CREATE UNIQUE INDEX [MYINDEX1] ON [dbo].[LOGIN_TABLE]([Loginid],
> logindate]) ON [PRIMARY]
> GO
> Do I still need to create the following index ?
>
> CREATE INDEX [MYINDEX2] ON [dbo].[LOGIN_TABLE]([Loginid]) ON [PRIMARY]
> GO
>
> Thanks for any feedback........
|||That's what I thought............Thanks.
"Paul Wehland" wrote:

> No. MYINDEX2 is redundant. SQL Server can use MYINDEX1 if it needs to seek
> on Loginid
>
> "DXC" <DXC@.discussions.microsoft.com> wrote in message
> news:34A7F75B-5178-4DD1-BD31-AFEE69C13458@.microsoft.com...
>
>