Currently, Query (in both database view and web view) does not allow the GFLink (the field that indicates which pledge a payment or write-off is connected to) to be added to the output. Without this field it is impossible to connect a pledge payment or write-off to the original pledge, which in turn makes it very difficult to report on pledges.
A note on the workaround: This works for pledge payments but does not appear to work for write offs. Both need to be connected to a pledge to get an accurate picture of what's happening with the pledge. A pledge for $500, for example, isn't really a $500 gift if $200 was written off. The lack of the GFLink field makes it difficult to capture these sorts of situations.
Yes, please get this fixed before database view goes away. Meanwhile, here's the workaround: https://kb.blackbaud.com/knowledgebase/Article/75198