Sql query, count and group by

Question

if i have data like this:

Key Name
1   Dan
2   Tom
3   Jon
4   Tom 
5   Sam
6   Dan

What is the sql query to bring back the records where the Name is repeated 2 or more times.

So the result i would want is

 Tom
 Dan

Answer 1

Couldn't be simpler...

Select
Name,
Count(Name) As Count
From
Table
Group By
Name
Having
Count(Name) > 1
Order By
Count(Name) Desc

This could also be extended to delete duplicates:

Delete
From
Table
Where
Key In (
    Select
    Max(Key)
    From
    Table
    Group By
    Name
    Having
Count(Name) > 1)

Answer 2

This could also be accomplished by joining the table with itself,

SELECT DISTINCT t1.name
FROM    tbl t1
        INNER JOIN tbl t2
        ON      t1.name = t2.name
WHERE   t1.key         != t2.key;

Answer 3

select name from table group by name having count(name) > 1