topr8 - 7:24 pm on Mar 25, 2012 (gmt 0)
either have 4 fields for each day.
first open,first closed, second open, second close
(that's assuming that shops only ever (potentially) close for lunch and not twice a day)
so you have an extra 28 fields in the table per store
then build a php function to calculate the opening times on the page.
there can only be so many open/close sequences.
create an extra table with one row for each variation and reference the id field in your businesses table.