The following example will cause COPY to fail on input:
xxx|yyy|zzz||aaa|bbb|
where the empty field in between zzz & aaa is of type datetime (don't know
about other types). I know a \N will fix this, but interpreting an empty
import field as NULL would certainly beef up COPY as other database systems
don't output the \N which is unique to PostgreSQL. Wish list item?
Ken