Question : about  ORA-00904: "ZIP": invalid identifier

Hi guys, I have this Ziptable and when I do

select * from ziptable; then it shows the result.....

But if I do select * from ziptable where Zip='02642';

Then error message comes....ORA-00904: "ZIP": invalid identifier

the datatype of the coloumns are fine.......

My zip table is.....

EDIT zip city State
 1420 Fitchburg MA
 02642 Harley PA
 02145 Bridgewater MA
 01624 Crusetown AK
 03428 Berkley CA
 03142 Manchester FL
 01234 Highland RI
 02143 Somerville MA
 05639 Portsmouth AZ
 09312 Oakland CT
 05423 Oakland FL
 02312 Harrinburgh AL


Please help me guys....  Thanks in advance

Answer : about  ORA-00904: "ZIP": invalid identifier

is your ojbect names case sensitive?

But if I do select * from ziptable where zip='02642';