SQLite handles dates quite strangely. If you create a table and put a date in it, the only way SQLite will take the input is "2004-06-01 12:00:00" anything else it won't recognize as a date and thus none of the date functions will work.
Assuming you have a date entered propely (like above) you get date information from the db like so.
SELECT date(DateField) FROM Table;
SELECT time(DateField) FROM Table;
SELECT datetime(DateField) FROM Table;
If you want unix time (seconds since the epoch) you have to format the output.
SELECT strftime("%s", DateField) FROM Table
However that will return the time in UTC which is probably not what you want (it's not what I wanted). I want it to compensate for my local timezone and thus you have to tell it to use your timezone.
SELECT strftime("%s", DateField, 'localtime') FROM Table
This will go the other way. Take a unixtime, and convert it to a SQLite date format.
SELECT datetime(1092941466, 'unixepoch', 'localtime');
Some semi-official SQLite documentation on how it handles dates is availble on their wiki page.