Re: BUG #16768: PostgreSQL 12.5 - INSERT ON CONFLICT succeeds on data INSERT but does nothing on UPDATE - Mailing list pgsql-bugs

On Tue, Dec 8, 2020 at 5:02 PM PG Bug reporting form
<noreply@postgresql.org> wrote:
> The SQL below recreates my issue.  That is, the LAST insert statement DOES
> NOT update the accountinfo_test table value for 'balance' to 200.0 ... it
> remains at the previous value of 100.0.

I think that you need to UPDATE using the excluded.* pseudo table. For
example, "SET my_col = excluded.my_col". As things stand you're using
the target table itself. Technically the row is being updated, but
with the wrong values (the existing values rather than your intended
new successor values).

-- 
Peter Geoghegan