SQL query to return all rows that contain duplicate data from one field

Question

I have a table with card numbers and names. Some of those names are the same, meaning they have multiple cards. How can I select all the rows where the name occurs more than once?

Answer 1

Following may be the solution you are looking for

Select * from CardTable where cardid in ( select cardid from CardTable group by cardid having count(cardid) > 1)