>>Metin,
>>
>>In SQL Server you can not create an index using a function. Use a date range when looking for a date, e.g.
>>

>>select * from myTable where DateField >=@Today and DateField < @Tomorrow
>>

>
>Thank you all,
>I'll use Naomi's way. I use in first variable today 00:00 and second variable today 24:59:59 . I'm afraid of about performance in other ways. I'm not sure if sql server will use index with other ways...

Metin,

You didn't read my suggestion and suggested blogs carefully. Don't use 23:59:59, use

>=@Today and <@Tomorrow