CASE表达式是一个选项，但是-使其有效。例如像这样（注意，我修改了季节日期，以便它们实际上代表我们在学校学到的东西）。
样本数据：

SQL> with test (dates) as
  2  (select
  3  date '2005-06-01' from dual union all select
  4  date '2008-09-06' from dual union all select
  5  date '2010-12-25' from dual union all select
  6  date '2003-03-30' from dual union all select
  7  date '2001-08-31' from dual union all select
  8  date '2002-10-17' from dual union all select
  9  date '2007-05-20' from dual union all select
 10  date '2006-04-15' from dual union all select
 11  date '2007-02-18' from dual union all select
 12  date '2002-01-16' from dual
 13  )

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查询：

14  select dates,
 15         case when to_char(dates, 'mmdd') between '0321' and '0620' then 'Spring'
 16              when to_char(dates, 'mmdd') between '0621' and '0922' then 'Summer'
 17              when to_char(dates, 'mmdd') between '0923' and '1220' then 'Autumn'
 18              --
 19              when to_char(dates, 'mmdd') between '1221' and '1231'
 20                or to_char(dates, 'mmdd') between '0101' and '0320' then 'Winter'
 21         end as season
 22  from test;

DATES       SEASON
----------- ------
01-Jun-2005 Spring
06-Sep-2008 Summer
25-Dec-2010 Winter
30-Mar-2003 Spring
31-Aug-2001 Summer
17-Oct-2002 Autumn
20-May-2007 Spring
15-Apr-2006 Spring
18-Feb-2007 Winter
16-Jan-2002 Winter

10 rows selected.

SQL>

型

一种可能性是规范化输入日期，使其始终是同一年。在这个例子中，我使用表达式ADD_MONTHS(Dates, 12 * (2000 - EXTRACT(YEAR FROM Dates)))将其始终设置为2000年：

WITH cte AS (
    SELECT
        Dates,
        ADD_MONTHS(Dates, 12 * (2000 - EXTRACT(YEAR FROM Dates))) AS d2000
    FROM T1
)
SELECT
    Dates,
    CASE
        WHEN d2000 BETWEEN TO_DATE('20-Mar-2000', 'DD-MON-YYYY') AND
                           TO_DATE('20-Jun-2000', 'DD-MON-YYYY') THEN 'Spring'
        WHEN d2000 BETWEEN TO_DATE('21-Jun-2000', 'DD-MON-YYYY') AND
                           TO_DATE('21-Sep-2000', 'DD-MON-YYYY') THEN 'Summer'
        WHEN d2000 BETWEEN TO_DATE('22-Sep-2000', 'DD-MON-YYYY') AND
                           TO_DATE('20-Dec-2000', 'DD-MON-YYYY') THEN 'Autumn'
        ELSE 'Winter'
    END AS Season
FROM cte

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请注意，冬天跨越了两年，这会使我们与BETWEEN的比较失败。我通过处理ELSE案例中的冬天来避免这个困难。