Answer / ashu_deepu

2 NULL value can not b equal.

i just want to remind some imp. point about primary key.
d condition is
1) not null n
2) unique.
since 2 null value r unique dats why we require the 1st point of not null.

Answer / nhajare

Hi,
If you comapare null=null then it return 0 rows selected.
Check the result of this query...

select * from table_name where null=null;

Answer / sandeep kumar

select * from dual where null=null

no row return

Answer / naidu

NOT EQUAL AND AGAIN ANSWER IS NULL

Answer / kishore vakiti

select * from emp where null is null;

Answer / abhishek jaiswal

Decode will return true if we compare null to null value.
select decode(commission_pct,null,0) from employees

Answer / divi

Null is not equal to Null
Nor
Null is equal to Null

Answer / sureka

set serveroutput on;
DECLARE
D INTEGER :=NULL;
E INTEGER :=NULL;
BEGIN
IF (D = E) THEN
dbms_output.put_line('PASS');
ELSIF (D <> E) THEN
dbms_output.put_line('FAIL');
ELSE
dbms_output.put_line('NA');
END IF;
END;

will return NA

Answer / archana

begin
if null is null then
dbms_output.put_line('null');
else
dbms_output.put_line('not null');
end if
end;

now it will return null
it is recommended to use 'is' with null not ' ='

Answer / kuldeep123

DECLARE
v1 NUMBER;
v2 NUMBER;
BEGIN
IF v1 = v2
THEN
DBMS_OUTPUT.put_line ('Null comapred successfully');
ELSE
DBMS_OUTPUT.put_line ('oops u have to use ISNULL opeartor');
END IF;
END;


output : oops u have to use ISNULL opeartor

What is the difference between cross join and natural join?

0 Answers  

What is the use of & in pl sql?

0 Answers  

what is the difference between sql and t-sql? : Transact sql

0 Answers  

Difference between SUBSTR and INSTR?

3 Answers  

What is difference between hql and native sql?

0 Answers  

using subquery how can i calculate working days in a month?

3 Answers   Spice Telecom,

What is the difference between sql and mysql?

0 Answers  

What is pl sql collection?

0 Answers  

Explain the structure of pl/sql in brief.

0 Answers  

Authentication mechanisms in Sql Server ?

1 Answers   BirlaSoft,

there are 2 variables called x and y ,x contains 1,2 and y contains 3,4 we have to swap the values from x to y and y to x with out using dummy variables and it can be done only by using a single statement ? how?

12 Answers   Oracle,

what is cross join? : Sql dba

0 Answers