如何在Oracle上使用SQL获取当前年份？

Question

我需要将当前年份添加为SQL语句中的变量,如何使用SQL检索当前年份？

即

  BETWEEN 
    TO_DATE('01/01/**currentYear** 00:00:00', 'DD/MM/YYYY HH24:MI:SS')
    AND
    TO_DATE('31/12/**currentYear** 23:59:59', 'DD/MM/YYYY HH24:MI:SS')

Answer 1

使用to_char:

select to_char(sysdate, 'YYYY') from dual;

在您的示例中,您可以使用以下内容:

BETWEEN trunc(sysdate, 'YEAR') 
    AND add_months(trunc(sysdate, 'YEAR'), 12)-1/24/60/60;

比较值正是您所要求的:

select trunc(sysdate, 'YEAR') begin_year
     , add_months(trunc(sysdate, 'YEAR'), 12)-1/24/60/60 last_second_year
from dual;

BEGIN_YEAR  LAST_SECOND_YEAR
----------- ----------------
01/01/2009  31/12/2009

Answer 2

另一种选择是:

SELECT *
  FROM TABLE
 WHERE EXTRACT( YEAR FROM date_field) = EXTRACT(YEAR FROM sysdate) 

Answer 3

使用extract(datetime)功能它简单易行.

它返回年,月,日,分,秒

例:

select extract(year from sysdate) from dual;