so create your query
set an appropriate ORDER BY clause
and use LIMIT X where X is the number of rows to reutrn
so thats
SELECT my,column,list FROM mytable
WHERE acondition evaluates as true /*such as ColumnA < 9.37 */
ORDER BY a,column,list
LIMIT 5
MySQL :: MySQL 5.1 Reference Manual :: 12.2.8 SELECT Syntax
bear in mind that databases have no concept of the first or last or whatever records unless you specify an order. the data is stuffed into a table and will be retrieved depending on some criteria the db decides (that may be the primary key, that may be the last index used, it may be the phase of the moon)