db Tweaking question

[netfrugal]

Is it better to have one table with many columns, or to have more tables with fewer columns?

I have a table with many records, and I am considering taking out the columns that are viewed less (or of less importance - but needed from time to time) and placing them in separate tables.

Anyone with good database knowledge on this?

[laserlight]

Why not select only those columns that you need instead of doing a SELECT *?