select to_date((to_char(sysdate,'yyyy')+1)||'0101','yyyymmdd')-to_date(to_char(sysdate,'yyyy')||'0101','yyyymmdd') from dual;//当年日历天数
select to_date((to_char(sysdate,'yyyymm')+1)||'01','yyyymmdd')-to_date(to_char(sysdate,'yyyymm')||'01','yyyymmdd') from dual;//当月日历天数
select to_date((to_char(sysdate,'yyyymm')+1)||'01','yyyymmdd')-to_date(to_char(sysdate,'yyyymm')||'01','yyyymmdd') from dual;//当月日历天数
SQL> select to_char(last_day(sysdate),'dd') from dual;TO
--
31已选择 1 行。
SQL> select to_char(trunc(sysdate,'yyyy') + interval '1' year -1,'ddd') from dual;TO_
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365