Depends entirely on what you want to do. Here's the basics, there are all kinds of variations on these.

1) retrieve data

"Select * from tablename where fieldname='something'"

2) modify existing data

"Update tablename set fieldname='something' where fieldname='something'"

3) add data to table

"insert into table values ('fld1', 'fld2' ...'lastfld')"

4) delete data from table

"delete tablename where fieldname='something'"