>Hi,
>
>I fount the following script online designed to create an index:
>
>

>CREATE NONCLUSTERED INDEX [MyTableIndex]
>ON [dbo].[tablename] ([tablename_ID],[tablename_Field1])
>INCLUDE ([Tablename_Field2],[Tablename_Field3])
>

>
>What I don't understand is the purpose of the INCLUDE syntax. I am actually trying to create a simple index on column REC_ID and
>I think that my syntax should be:
>
>

>CREATE NONCLUSTERED INDEX [MyTableIndex]
>ON [dbo].[tablename] ([rec_id])
>

>
>But I want to be sure that I am not missing something important with this INCLUDE. Can anybody explain? TIA.

You may include columns into the index to create covering index.

This blog post has information about it http://blogs.lessthandot.com/index.php/DataMgmt/DataDesign/sql-server-covering-indexes