Variable values in Views

Hi List,
I have a view that works fine as-is, but I want to make it dynamic,
replacing a few values with variables.

SELECT

There are two variables:
*$date_string* which will contain a string such as "-7 days" or "-1 month".

and
*$table_prefix* which will be a number indicating which table set to look
in.

I know SQLite can't do variables (for example
http://sqlite.1065341.n5.nabble.com/Using-local-variables-through-sqlite-td21270.html)
but does anyone have any suggestions for how this can be done? I don't want
to have to create tons of extra views if I don't have to.

Thanks,
Jonathan