一段时间关系的SQL

T1

CCN,ORDATE,NUM
C,2013-01-05,12
C,2013-01-25,14
C,2013-02-03,21
......
T2
YEAR,BEGIN,P1,P2
2013,2013-01-01,2013-01-26,2013-02-20
......



如果T1.ORDATE的时间在T2的BEGIN到P1，那后面加一个字段P1,如果是在P1到P2之间值就是P2

CCN,ORDATE,NUM,PER
C,2013-01-05,12,P1
C,2013-01-25,14,P1
C,2013-02-03,21,P2
[解决办法]

select t1.*,
       case
         when t1.ORDATE between t2.BEGIN and t2.p1 then
          'P1'
         when t1.ORDATE between t2.p1 and t2.p2 then
          'P2'
       end
  from t1, t2
 where to_char(t1.ORDATE, 'yyyy') = t2.year