I have a "registration" new table with some fields like Guid, ClientGuid, RegistrationDate, DeregistartionDate, Status, Created and LastUpdate.

I have another table with almost 5000 records and the table name is "Client" with so many fields including Guid, RegistrationDate, DeregistartionDate.

Now i want to put Guid, RegistrationDate, DeregistartionDate data from client table and put this date in "registration" table.

i wrote a queary like this but its not working.. it says #1062 - Duplicate entry '' for key 'PRIMARY'

INSERT INTO `registration` (`ClientGuid`, `RegistrationDate`,`DeregistrationDate`)
SELECT `Guid`, `RegistrationDate`, `DeregistrationDate` FROM `Client`;

Thanks in advance..