John W Higgins wrote:
On Wed, Dec 5, 2018 at 4:34 PM Phil Endecott <
spam_from_pgsql_li...@chezphil.org> wrote:
Dear Experts,
I have a couple of tables that I want to reconcile, finding rows
that match and places where rows are missing from one table or the
other:
...
So my question is: how can I modify my query to output only two rows,
like this:?
+------------+--------+------------+--------+
| date | amount | date | amount |
+------------+--------+------------+--------+
| 2018-01-01 | 10.00 | 2018-01-01 | 10.00 |
| 2018-02-01 | 5.00 | | |
| | | 2018-03-01 | 8.00 |
| 2018-04-01 | 5.00 | 2018-04-01 | 5.00 |
| 2018-05-01 | 20.00 | 2018-05-01 | 20.00 | 1
| 2018-05-01 | 20.00 | 2018-05-01 | 20.00 | 2
+------------+--------+------------+--------+
Evening Phil,
Window functions are your friend here. I prefer views for this stuff - but
subqueries would work just fine.
create view a_rows as (select *,
row_number() OVER (PARTITION BY date, amount) AS pos
from a);
create view b_rows as (select *,
row_number() OVER (PARTITION BY date, amount) AS pos
from b);
select
a_rows.date,
a_rows.amount,
a_rows.pos,
b_rows.date,
b_rows.amount,
b_rows.pos
from
a_rows full join b_rows using (date,amount,pos);
Thanks John, that's great. I'm a little surprised that there isn't an
easier way, but this certainly works.
Regard, Phil.
