Math Functions:
===============
1) abs():
---------
=> convert the negative number into positive number.
Syntax:
	abs(-number);

|-9| ==> 9
|8| ==> 8

Query: select abs(-97) from dual;

2) round():
-----------
round(9.5) ==> 10
round(9.4) ==> 9

=> round() can accept the floating-point value
can return the nearest integer value.
Syntax:
	round(any-float-value);

Query:
select round(9.5) from dual;
select round(9.4) from dual;

3) floor():
----------
floor(9.5) ==> 9

=> floor() can accept a floating-point value
and returns nearest smallest integer value.
syntax:
	floor(floating-point-value)

Query:
	select floor(9.6) from dual;

4) ceil():
---------
ceil() can accept a floating-point value
and returns the nearest higher integer value.
Syntax:
	ceil(float-value);

Query:
	select ceil(9.5) from dual;

5) greatest():
--------------
salries {78000,100000,20000,77000,40000,50000,150000}
greatest(salaries) ==> 150000

=> greatest() can accept list of values
and return the maximum value from the list.

Syntax:
	greatest(list-of-values);

6) least():
-----------
=> least() can accept list of values
and returns the minimum value of the collection.
Syntax:
	least(list-of-values);

Ex: salaries {23000,18000,33000,55000,170000,59000}
least(salaries) ==> 17000;

Query:
select least(23000,22500,55000,17000,18000,99000,150000) from dual;

7) mod():
---------
% ==> division
a % b ==> remainder

mod() ==> returns the remainder
=> mod() can accept two values
returns the remainder by division operation
Syntax:
	mod(v1, v2);

8) sqrt():
----------
=> sqrt() can accept a value
and returns a square root of that value
Syntax:
	sqrt(value);

9) power():
---------
=> power() can accept two values
and return a value as power of the specified values.
Syntax:
	power(a, b);

Here:
	result = a ^ b

10) log():
----------
=> to find the logarithm of any number, we can use "log()".
Syntax:
	log(value, base);

here:
	base ==> 10 or 2

Query: select log(10,10) from dual;
select log(10,2) from dual;

11) sin() ==> to get the sin angle 
Syntax:
	sin(any-value)

12) cos() ==> to get the cos angle
Syntax:
	cos(any-value)

13) tan() ==> to get the tan angel
Syntax:
	tan(any-value)


Date Handling Functions:
========================
1) add_months():
----------------
=> add_months() can accept two values:
	1) date ==> current date (sysdate) or
		any formatted date 'dd-Mon-YYYY'
	2) number ==> number of months
Syntax:
	add_months(date, number);
=> to the given date, the number in months can add and return the new date.

Query:
	select add_months(sysdate, 12) from dual;
	select add_months('20-Jun-1993', 100) from dual;

2) last_day():
--------------
=> last_day() can accept a date
for that date's last day in the month can be returned.
Syntax:
	last_day(date);

Query:
	select last_day(sysdate) from dual;
	select last_day('19-Nov-2005') from dual;

3) next_day():
--------------
next_day() can accept two values:
	1) date ==> from which date we need to get the next date
	2) day ==> which day from the specified date we are expecting
Syntax:
	next_day(date, day);

Query:
	select next_day(sysdate, 'Saturday') from dual;