Question

I am having some trouble wrapping my head around this one.

I have a Cars Database with a Class field that when selecting all entries, it will have duplicates of each Class value. What I need to do with that is to count all of duplicates for each Class value and then remove the duplicates to only display each Class value once with a custom fields with the counted amount.

Class  
-----  
A3  
A3  
A3  
A3  
B2  
B2

To become:

Class | Count  
------+---------  
A3    | 4  
B2    | 2

I could imagine something contain the Count() method, but I have no idea how I could have it count only the duplicate values and return the values separately for each Class value?

Thanks in advance for any help in this one.

Answer 1

SELECT Class,COUNT(1) "Count"
FROM Cars GROUP BY Class
HAVING COUNT(1) > 1;