Convert Date function to oracle

Question

The follwoing Sql for Sqlserver, what is the equivalent function in oracle. Need help on this.
YTD:
YOUR_DATE_FIELD between DATEADD(yy,
DATEDIFF(yy,0,@Prompt('BEGIN_DATE','D',,mono,free)), 0) AND
@Prompt('END_DATE','D',,mono,free)
MTD:
YOUR_DATE_FIELD between DATEADD(mm, DATEDIFF(mm, 0,
,@Prompt('BEGIN_DATE','D',,mono,free)), 0) AND
@Prompt('END_DATE','D',,mono,free)
WTD
YOUR_DATE_FIELD between (,@Prompt('BEGIN_DATE','D',,mono,free) -
DATEPART(dw, ,@Prompt('BEGIN_DATE','D',,mono,free)))+1 AND
@Prompt('END_DATE','D',,mono,free)

Answer 1

Extracting month,year,day from sysdate (You may even opt to use to_char)
SQL> select extract (month from sysdate) from dual;
EXTRACT(MONTHFROMSYSDATE)
                        4
SQL> select extract (year from sysdate) from dual;
EXTRACT(YEARFROMSYSDATE)
                    2007
SQL> select extract (day from sysdate) from dual;
EXTRACT(DAYFROMSYSDATE)
                      5
Adding 5 days to today's date
SQL> select sysdate + 5 from dual;
SYSDATE+5
10-APR-07
Adding Months
SQL> select add_months(sysdate,3) from dual;
ADD_MONTH
05-JUL-07
Date Difference
SQL> select sysdate - to_date('01/04/2007','dd/mm/yyyy') from dual;
SYSDATE-TO_DATE('01/04/2007','DD/MM/YYYY')
                                4.42670139
Date Difference
SQL> select trunc(sysdate) - trunc(to_date('01/04/2007','dd/mm/yyyy')) from dual
TRUNC(SYSDATE)-TRUNC(TO_DATE('01/04/2007','DD/MM/YYYY'))
                                                       4
SQL>