Hi there,
if I order a given year in DESCending ORDER, so that the highest
values (of a given variable) for the countries are displayed at
the top of the list, then actually the NULL values appear as
first. Only below, I find the values ordered correctly.
Is there any way to
a) make the countries with NULL values appear at the bottom of
the list
b) neglect the NULL values by still allowing the countries to
be displayed
Not sure what you mean by (b), but (a) is straightforward enough.
=> SELECT * FROM (SELECT 1 as a UNION SELECT 2 UNION SELECT
null::int) AS foo ORDER BY (a is null), a DESC;
a
---
2
1
(3 rows)
Looks easy.
If I apply this to my SQL:
SELECT
SUM(CASE WHEN year=2002 THEN value ELSE NULL END) AS "y_2002",
SUM(CASE WHEN year=2001 THEN value ELSE NULL END) AS "y_2001",
SUM(CASE WHEN year=2000 THEN value ELSE NULL END) AS "y_2000",
c.name AS name
FROM
aquacult_prod_marine AS d
LEFT JOIN
countries AS c ON c.id = id_country
GROUP BY
name
ORDER BY
y_2000 DESC
I would then say:
ORDER BY
(y_2000 is null),
y_2000 DESC
But then I get an Error warning:
ERROR: column "y_2000" does not exist
What do I do wrong?
---------------------------(end of broadcast)---------------------------
TIP 9: In versions below 8.0, the planner will ignore your desire to
choose an index scan if your joining column's datatypes do not
match
