What is the result, when NULL is compared with NULL?
Answers were Sorted based on User's Feedback
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.
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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;
Is This Answer Correct ? | 1 Yes | 0 No |
Answer / sandeep kumar
select * from dual where null=null
no row return
Is This Answer Correct ? | 1 Yes | 0 No |
Decode will return true if we compare null to null value.
select decode(commission_pct,null,0) from employees
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Answer / divi
Null is not equal to Null
Nor
Null is equal to Null
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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
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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 ' ='
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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
Is This Answer Correct ? | 0 Yes | 0 No |
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