Hemant,
you have to use only one combination with Upper or Lower.

select name from name_table
where UPPER(name) = ' KRISHNA';

will return ALL the rows --

name
-----------
Krishna
KRishna
KRishnA
kRiSHNa
KriSHNA
KRISHNa
KRISHNA
KriShNa

- Rajeev