skupina podle klauzule dotazu

Zkuste toto pro vybrané:

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

Zkuste toto pro odstranění (upravená verze @RedFilter's):

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