Oracle PL/SQL Programming: A Developer's Workbook

Expert

19-17.	Write a function that returns the date of the nearest day named to the specified date, as in: FUNCTION nearestday ( yourdate IN DATE, dayname IN VARCHAR2) RETURN DATE;
19-18.	Write a function to return the number of business days (defined in this exercise as all days that are not Saturdays and Sundays) between two dates. Here is the header: FUNCTION bizdays_between ( start_date IN DATE, end_date IN DATE) RETURN INTEGER;
19-19.	Enhance the “business days between” function to also subtract from total the number of holidays stored in the following table: CREATE TABLE holiday (dt DATE);
19-20.	Write a function that returns the nth named day in the month in which the specified date is located. Here is the header for such a function: FUNCTION nthday ( yourdate IN DATE, dayname IN VARCHAR2, nthday IN INTEGER) RETURN DATE; and here is the expected behavior: SQL> EXEC DBMS_OUTPUT.PUT_LINE(nthday(SYSDATE,'monday',1)) February 1, 1999 00:00:00 SQL> EXEC DBMS_OUTPUT.PUT_LINE(nthday(SYSDATE,'monday',2)) February 8, 1999 00:00:00 SQL> EXEC DBMS_OUTPUT.PUT_LINE(nthday(SYSDATE,'monday',3)) February 15, 1999 00:00:00 SQL> EXEC DBMS_OUTPUT.PUT_LINE(nthday(SYSDATE+30,'monday',5)) March 29, 1999 00:00:00
19-21.	I discovered recently (March 1999) that the documented maximum allowable date in PL/SQL had changed from the long-standing December 31, 4712. How did I discover this? A visitor to the PL/SQL Pipeline found that he could work with dates well beyond this “limit.” He wondered what the actual limit ...