Using seek in index of a table in a query

[apro]

Hi, I would like to use if possible a seek statement that takes me to the first range of a data on the indexed table column. Then be able to run formulas on the given range and continue on the next range do the same thing until the the end of the table, instead of scanning the whole table for each range.
If you could post me a Select statement example or what you think can do the job using index I would appreciate. Also I would like to know if this is an efficient way of retreiving ranges of data while running formulas on each range

Thanks

[rmiao]

On which rdbms?

[apro]

On SQL Server

[rmiao]

There's no seek statement in sql server. Can you post table schema, same sample data and result you like to get?