Limiting query results

First 100 rows

SELECT *
FROM   SOME_TABLE
LIMIT  100;

First 100 rows of an ordered set

SELECT *
FROM   SOME_TABLE
ORDER BY ORDER_COLUMN
LIMIT 100; -- LIMIT applies after ORDER BY

Or with analytic functions

SELECT Q.*
FROM (
  SELECT T.*,
         ROW_NUMBER() OVER(ORDER BY ORDER_COLUMN)   RNUM
  FROM   SOME_TABLE  T)  Q
WHERE RNUM <= 100;