This will substitutes the specified value in the place of null values.
Syntax: nvl (null_col, replacement_value)
Ex:
SQL> select * from student; --
here for 3rd row marks value is null
NO NAME
MARKS
--- ------- ---------
1
a 100
2 b 200
3 c
SQL> select no,
name, nvl(marks,300) from student;
NO NAME NVL(MARKS,300)
--- -------
---------------------
1 a 100
2 b 200
3 c 300
SQL> select
nvl(1,2), nvl(2,3), nvl(4,3), nvl(5,4) from dual;
NVL(1,2)
NVL(2,3) NVL(4,3) NVL(5,4)
----------
---------- ---------- ----------
1
2 4 5
SQL> select
nvl(0,0), nvl(1,1), nvl(null,null), nvl(4,4) from dual;
NVL(0,0)
NVL(1,1) NVL(null,null) NVL(4,4)
----------
---------- -----------------
----------
0 1 4
