oracle ifelse sql 语句

sql1：

select sfwb
from tab_jxgd

运行：

sql2:

select (CASE sfwb WHEN 'y' THEN '是' ELSE '否' END) sfwb
from tab_jxgd

运行：

1.select * from t_meetting_application t where to_date('2010-10-27 10:30:00', 'yyyy-mm-dd hh24:mi:ss') between t.starttime and t.endtime
2.select * from t_meetting_application t where t.starttime between to_date('2010-10-27 1:30:00', 'yyyy-mm-dd hh24:mi:ss') and to_date('2010-10-27 13:30:00', 'yyyy-mm-dd hh24:mi:ss')