Use floor and mod to get the number of days : FLOOR « Numerical Math Functions « Oracle PL/SQL Tutorial

SQL>
SQL> create table employees(
  2    empno      NUMBER(4)
  3  , ename      VARCHAR2(8)
  4  , init       VARCHAR2(5)
  5  , job        VARCHAR2(8)
  6  , mgr        NUMBER(4)
  7  , bdate      DATE
  8  , msal       NUMBER(6,2)
  9  , comm       NUMBER(6,2)
 10  , deptno     NUMBER(2) ) ;

Table created.

SQL>
SQL>
SQL> insert into employees values(1,'Jason',  'N',  'TRAINER', 2,   date '1965-12-18',  800 , NULL,  10);

1 row created.

SQL> insert into employees values(2,'Jerry',  'J',  'SALESREP',3,   date '1966-11-19',  1600, 300,   10);

1 row created.

SQL> insert into employees values(3,'Jord',   'T' , 'SALESREP',4,   date '1967-10-21',  1700, 500,   20);

1 row created.

SQL> insert into employees values(4,'Mary',   'J',  'MANAGER', 5,   date '1968-09-22',  1800, NULL,  20);

1 row created.

SQL> insert into employees values(5,'Joe',    'P',  'SALESREP',6,   date '1969-08-23',  1900, 1400,  30);

1 row created.

SQL> insert into employees values(6,'Black',  'R',  'MANAGER', 7,   date '1970-07-24',  2000, NULL,  30);

1 row created.

SQL> insert into employees values(7,'Red',    'A',  'MANAGER', 8,   date '1971-06-25',  2100, NULL,  40);

1 row created.

SQL> insert into employees values(8,'White',  'S',  'TRAINER', 9,   date '1972-05-26',  2200, NULL,  40);

1 row created.

SQL> insert into employees values(9,'Yellow', 'C',  'DIRECTOR',10,  date '1973-04-27',  2300, NULL,  20);

1 row created.

SQL> insert into employees values(10,'Pink',  'J',  'SALESREP',null,date '1974-03-28',  2400, 0,     30);

1 row created.

SQL>
SQL>
SQL> select ename
  2  ,      floor(mod(sysdate-bdate,7)) as days
  3  from   employees;

ENAME          DAYS
-------- ----------
Jason             5
Jerry             5
Jord              5
Mary              4
Joe               5
Black             6
Red               6
White             6
Yellow            6
Pink              0

10 rows selected.

SQL>
SQL>
SQL> drop table employees;

Table dropped.

SQL>
SQL>

14.12.FLOOR
	14.12.1.	FLOOR(x) gets the largest integer less than or equal to x.
	14.12.2.	Use FLOOR function to get the flooring value
	14.12.3.	FLOOR for negative value
	14.12.4.	FLOOR(5.8)
	14.12.5.	FLOOR(-5.2)
	14.12.6.	select round(345.678), ceil(345.678), floor(345.678)
	14.12.7.	Use floor to get the number of weeks
	14.12.8.	Use floor and mod to get the number of days