How to define this SQL ?

Hi all,

I'm going to retrieve a field whose content contain date and time, i.e. 2005071300045678.

I only want to retrive the date, i.e. the first 8 offsets.

I've done something like:

Select * from db where field1+0(8) = '20050713'.

But the system can't identify field1+0(8),

what should I do?

Thanks.