groeperen op clausule query

Probeer dit voor de select:

SELECT * FROM Table
GROUP BY CustomerName
HAVING SUM(LocalAmount) > 50000

Probeer dit om te verwijderen (aangepaste versie van @RedFilter's):

delete from MyTable 
where CustomerName in (
    select CustomerName 
    from Table
    group by CustomerName 
    having sum(LocalAmount) <= 50000
)