ORDER BY column, with specific notnull value LAST

When I discovered NULLS LAST, I kinda hoped it could be generalised to 'X LAST' in a CASE statement in the ORDER BY portion of a query.

Not so, it would seem.

I'm trying to sort a table by two columns (easy), but get the output in a specific order (easy), with one specific value of one column to appear last (got it done... ugly).

Let's say that the columns are zone and status (don't blame me for naming a column zone - I didn't name them). status only takes 2 values ('U' and 'S'), whereas zone can take any of about 100 values.

One subset of zone's values is (in pseudo-regexp) IN[0-7]Z, and those are first in the result. That's easy to do with a CASE.

zone can also take the value 'Future', which should appear LAST in the result.

In my typical kludgy-munge way, I have simply imposed a CASE value of 1000 as follows:

group by zone, status
order by (
 case when zone='IN1Z' then 1
      when zone='IN2Z' then 2
      when zone='IN3Z' then 3
        .
        . -- other IN[X]Z etc
        .
      when zone = 'Future' then 1000
      else 11 -- [number of defined cases +1]
      end), zone, status

This works, but it's obviously a kludge, and I wonder if there might be one-liner doing the same.
Is there a cleaner way to achieve the same result?

Solution

Postgres allows boolean values in the ORDER BY clause. For your generalised 'X LAST':

ORDER BY (my_column = 'X')

The expression evaluates to boolean, which sorts this way:

false  -- think '0'
true   -- think '1'
null   -- NULLS LAST is default sort order

Since we deal with notnull values, that's all we need. Here is your one-liner:

ORDER BY (zone = 'Future'), zone, status;