Datediff when date held in one field?!

[DeviousDi]

Hi,

I'm hoping someone can help me here, as I can't seem to get my head round what I should do!

First off, I'm using SAP CR XI.

I have to following fields and results:

QueryID ChangeID QueryDate OldQueryGrp NewQueryGrp DateChanged

189 220 23/11/12 7 23/11/12
189 453 23/11/12 7 3 03/01/13
189 529 23/11/12 3 2 17/01/13


629 227 26/11/12 7 26/11/12
629 470 26/11/12 7 3 04/01/13
629 9836 26/11/12 3 9 24/05/13
629 77384 26/11/12 9 2 06/09/13
629 83004 26/11/12 2 5 17/09/13
629 85337 26/11/12 5 2 19/09/13


What I need to show to the powers that be are the number of days spent in each query group. Eg, query 189 spent 41 days in query group 7.

I know you can do a datediff, but how do you do a datediff when the dates are all held within one field?

I should also add, there is no 'set' routine as to what query group follows what, and they can go backwards and forwards!

Any help would be much appreciated!

Thanks

Di