Re: ORDER BY - problem with NULL values

>> 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?