CASE表达式

SELECT

  -- Searched case
  CASE WHEN AUTHOR.FIRST_NAME = 'Paulo'  THEN 'brazilian'
       WHEN AUTHOR.FIRST_NAME = 'George' THEN 'english'
                                         ELSE 'unknown'
  END,

  -- Simple case
  CASE AUTHOR.FIRST_NAME WHEN 'Paulo'  THEN 'brazilian'
                         WHEN 'George' THEN 'english'
                                       ELSE 'unknown'
  END
FROM AUTHOR

create.select(

  // Searched case
  when(AUTHOR.FIRST_NAME.eq("Paulo"), "brazilian")
  .when(AUTHOR.FIRST_NAME.eq("George"), "english")
  .otherwise("unknown");

  // Simple case
  choose(AUTHOR.FIRST_NAME)
  .when("Paulo", "brazilian")
  .when("George", "english")
  .otherwise("unknown"))
.from(AUTHOR)
.fetch();

SELECT AUTHOR.FIRST_NAME, [... CASE EXPR ...] AS nationality
  FROM AUTHOR