DB2 sql上期（月、季、年）上月月末，上季末，上年末(统计中常用到)
SELECT
current timestamp -day(current date) days ,-- 上个月月末 ,能够知道跨年
/*
to_date('2013-02-23','yyyy-mm-dd') -day(current date) days ,-- 上个月月末 ,能够知道跨年 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 , -- 上个季月 能够知道跨年
current date - (month(current date) -1 ) month - day(current date) day --上年年末
from sysibm.sysdummy1;