MySQL UNION Only Includes First Table - mysql

Question

I need to perform a FULL OUTER JOIN on two tables and I'm trying to implement it in MySQL using the LEFT JOIN/RIGHT JOIN/UNION ALL technique.
Here are the original tables:
giving_totals:
+--------------+---------------+-------------+
| country_iso2 | total_given | supersector |
+--------------+---------------+-------------+
| AE | 1396986989.02 | 3 |
| AE | 596757809.20 | 4 |
| AE | 551810209.87 | 5 |
| AE | 25898255.77 | 7 |
| AE | 32817.63 | 9 |
...
+--------------+---------------+-------------+
receiving_totals:
+--------------+----------------+-------------+
| country_iso2 | total_received | supersector |
+--------------+----------------+-------------+
| AE | 34759000.00 | 3 |
| AE | 148793.82 | 7 |
| AE | 734.30 | 9 |
| AF | 6594479965.85 | 1 |
| AF | 2559712971.26 | 2 |
+--------------+----------------+-------------+
I want the resulting table to have one entry for each country for each supersector code even if it did not give or receive money for that sector (this is from the AidData project dataset in case anyone is familiar.) I thought to accomplish this by doing a UNION of a LEFT JOIN (to get all giving entries) and RIGHT JOIN (to get all receiving entries.) Here's the query I tried:
SELECT g.country_iso2 AS country_iso2, g.total_given AS `total_given`,R.total_received AS `total_received`,g.supersector AS `supersector`
FROM (`giving_totals` `g`
LEFT JOIN `receiving_totals` `r`
ON(((g.country_iso2 = r.country_iso2)
AND (g.supersector = r.supersector))))
UNION ALL
SELECT g.country_iso2 AS country_iso2, g.total_given AS `total_given`,R.total_received AS `total_received`,g.supersector AS `supersector`
FROM (`giving_totals` `g`
RIGHT JOIN `receiving_totals` `r`
ON(((g.country_iso2 = r.country_iso2)
AND (g.supersector = r.supersector))))
But this only returns the first join, whether or not I put the right or left join first. I think I may be misunderstanding the UNION operation because the individual joins each return what I expected. Any help is appreciated as always.

Answer 1

Here is an alternative method to do a full outer join:
SELECT driver.country_iso2 AS country_iso2,
g.total_given AS `total_given`,
R.total_received AS `total_received`,
driver.supersector AS `supersector`
from ((select distinct country_iso2, supersector
from giving_totals
) union
(select distinct country_iso2, supersector
from receiving_totals
)
) driver left outer join
giving_totals gt
on gt.country_iso2 = driver.country_iso2 and
gt.supersector = driver.country_iso2 left outer join
receiving_totals rt
on rt.country_iso2 = driver.country_iso2 and
rt.supersector = driver.country_iso2
That is, do the union as a subquery to get all the combinations you are interested in. Then you can do a left outer join to that table.
The reason for your problem is that aliases in the second query. You can try this instead:
SELECT r.country_iso2 AS country_iso2, g.total_given AS `total_given`,R.total_received AS `total_received`,r.supersector AS `supersector`
FROM (`giving_totals` `g`
RIGHT JOIN `receiving_totals` `r`
ON(((g.country_iso2 = r.country_iso2)
AND (g.supersector = r.supersector))))
The original form would have NULLs for these values.