How to get distinct record from mysql table?

I have a table student like this

id | name | zip 
1  | abc  | 1234
2  | xyz  | 4321
3  | asd  | 1234

I want to get all records but zip code should not be repeated. So In case of above table records, record No 1 and 2 should be fetched. Record No. 3 will not be fetched because it has a zip code which is already in record No. 1