Lets say I have a table with three columns:

id name field
1 test123 abc
2 test456 abc
3 test123 def
4 test456 abc
5 test789 abc

I want to select all "names" from the table which appear more than once and in which the field is not the same. In the above example, I should get one result back - the name "test123". How would I do that?