CREATE FUNCTION increment(INOUT result INTEGER, IN delta INTEGER)
     RETURNS INTEGER
BEGIN
  DECLARE code INTEGER DEFAULT 0;
  DECLARE SQLCODE INTEGER;
  DECLARE CONTINUE HANDLER FOR SQLEXCEPTION 
  BEGIN
       SET code = SQLCODE;
       RETURN code;
   END;
   SET result = result + delta;
   RETURN code;
END@

CREATE FUNCTION REVERSE(INSTR VARCHAR(4000))
     RETURNS VARCHAR(4000)
     DETERMINISTIC NO EXTERNAL ACTION CONTAINS SQL
BEGIN ATOMIC
     DECLARE REVSTR, RESTSTR VARCHAR(4000) DEFAULT '';
     DECLARE LEN INT;
     IF INSTR IS NULL THEN
       RETURN NULL;
     END IF;
     SET (RESTSTR, LEN) = (INSTR, LENGTH(INSTR));
     WHILE LEN > 0 DO
       SET (REVSTR, RESTSTR, LEN) 
       = (SUBSTR(RESTSTR, 1, 1) CONCAT REVSTR, 
       SUBSTR(RESTSTR, 2, LEN - 1),
       LEN - 1);
     END WHILE;
     RETURN REVSTR;
END

CREATE FUNCTION TAN (X DOUBLE)
     RETURNS DOUBLE
     LANGUAGE SQL
     CONTAINS SQL
     NO EXTERNAL ACTION
     DETERMINISTIC
     RETURN SIN(X)/COS(X)

CREATE FUNCTION DEPTEMPLOYEES (DEPTNO CHAR(3))
     RETURNS TABLE (EMPNO CHAR(6),
                    LASTNAME VARCHAR(15),
                    FIRSTNAME VARCHAR(12))
     LANGUAGE SQL
     READS SQL DATA
     NO EXTERNAL ACTION
     DETERMINISTIC
     RETURN
       SELECT EMPNO, LASTNAME, FIRSTNME
         FROM EMPLOYEE
         WHERE EMPLOYEE.WORKDEPT = DEPTEMPLOYEES.DEPTNO