SQL Update

[Uwe 111]

Hallo

Delphi-Quellcode:

SELECT a1.Name, a1.Sales, COUNT(a2.sales) Sales_Rank
FROM Total_Sales a1, Total_Sales a2
WHERE a1.Sales <= a2.Sales or (a1.Sales=a2.Sales and a1.Name = a2.Name)
GROUP BY a1.Name, a1.Sales
ORDER BY a1.Sales DESC, a1.Name DESC;

Result:
Name Sales Sales_Rank
Greg 50 1
Sophia 40 2
Stella 20 3
Jeff 20 3
Jennifer 15 5
John 10 6

Und nun zu mein Problem:
Wie kann ich es hinbekommen das Sales_Rank updatet?

MFG
Uwe 111