DB2 sql上期（月、季、年）上月月末，上季末，上年末(統計中常用到)

DB2 sql上期（月、季、年）上月月末，上季末，上年末(統計中常用到)   SELECT current timestamp -day(current  date) days ,-- 上個月月末 ,能夠知道跨年   /* to_date('2013-02-23','yyyy-mm-dd') -day(current  date) days ,-- 上個月月末 ,能夠知道跨年  www.2cto.com   */   CASE  WHEN  TO_CHAR('2012-06-22','Q') ='1' THEN  to_char(year('2012-12-01')-1)||'-12'  when  TO_CHAR('2012-06-22','Q') ='2' THEN to_char(year('2012-06-22'))||'-3' when  TO_CHAR('2012-01-01','Q') ='3' THEN to_char(year('2012-12-01'))||'-6' when  TO_CHAR('2012-01-01','Q') ='4' THEN to_char(year('2012-12-01'))||'-9'  END AS tt , -- 上個季月 能夠知道跨年   current date - (month(current date) -1 ) month - day(current date) day  --上年年末    from sysibm.sysdummy1;