PL/HQL allows you to handle exceptions in your programs.

Syntax:

BEGIN
  -- Statements that can raise an exception
EXCEPTION
  WHEN condition THEN 
    -- Statements
  WHEN condition2 THEN
    -- Statements2
    ...
END

Example:

DECLARE 
  v VARCHAR(200);
BEGIN
  OPEN cur FOR 'SELECT c1 FROM t1';
  FETCH cur INTO v;
  CLOSE cur;
EXCEPTION WHEN OTHERS THEN
  DBMS_OUTPUT.PUT_LINE('Error');
END

Compatibility: Oracle, PostgreSQL and Netezza.