$limit controls the maximum number of rows that will be returned.
$offset controls which row that will be the first in the result
set from the total amount of matching rows.
Example:
$q->select( '*' )->from( 'table' )
->limit( 10, 0 );
LIMIT is not part of SQL92. It is implemented here anyway since all
databases support it one way or the other and because it is
essential.