If we assume that the employee table, created by the following SQL statement:
CREATE MULTISET TABLE employee(empno INTEGER, ename VARCHAR(50), deptno INTEGER, jobstart DATE NOT NULL, jobend DATE NOT NULL, PERIOD FOR jobduration(jobstart, jobend)) PRIMARY INDEX(empno);
contains the following row:
INSERT INTO employee(1025, 'John', '999', DATE'2005-02-03', UNTIL_CHANGED);
The following SELECT statement:
SELECT empno,ename(CHAR(30)) FROM employee WHERE END(jobduration) IS UNTIL_CHANGED;
returns:
empno ename ------ ------ 1025 John