Tomasz Brzezina <biuro(at)sam(dot)w3(dot)pl> writes:
> document_id vat_type_id vat_type_value document_netto_value
> 65615 1 0 0
> 65615 4 0.07 -12.5327
> 65615 5 0.22 -7.31148
> 65615 5 0.22 -7.31148
Perhaps document_item_value is float4, and there is some low-order-bit
difference in the sums?
regards, tom lane