Say you have table of some items with these two columns: 

* ItemName
* Price

....where `ItemName` is unique.

How do you show sum of all prices for every `ItemName` (I'm using Oracle)? If I just try this:

```
SELECT ItemName, 
       SUM(Price)
  FROM Items

```

I get this error:

> 
> ORA-00937: not a single-group group
>  function
> 
> 
> 

...which goes away only if I use GROUP BY. But then I can SUM only by groups, not all of them.