Group By but include “missing” values

Question

Suppose I have the following.

select
  case
    when fcompany = \'Acme\' then \'Red\'
    when fcompany = \'Acme Rockets\' then \'Blue\'
    else \'Green\'
  en         


        

Answer 1

Move the GROUP into a conditional SUM with more columns?

select
  sum(CASE WHEN fcompany = 'Acme'
                     THEN fann_sales ELSE 0 END) AS redsales,
  sum(CASE WHEN fcompany = 'Acme Rockets'
                     THEN fann_sales ELSE 0 END) AS bluesales
  sum(CASE WHEN fcompany NOT IN ('Acme Rockets', 'Acme')
                     THEN fann_sales ELSE 0 END) AS greensales
FROM
  slcdpm

One pass over the table for this. A UNION ALL or subquery approach (in other answers) will touch the table once per clause = somewhat slower.