求一句SQL！

Question

表Tid    a               b  1   2008-9-10     2008-9-11  2   2008-9-11     2008-9-103   2008-9-12     2008-9-12比较a列和b列，a >= b 返回 ‘Y’，a < b 返回‘N'

Answer 1

select *,[顯示]=case when a>=b then 'Y' else 'N' end from Table

Answer 2

SQL> select * from t;                                     ID A           B
--------------------------------------- ----------- -----------
                                      1 9/10/08     9/11/08
                                      2 9/11/08     9/10/08
                                      3 9/12/08     9/12/08SQL> select id,a,b,case when a>=b then 'Y' else 'N' end compareResult from t;                                     ID A           B           COMPARERESULT
--------------------------------------- ----------- ----------- -------------
                                      1 9/10/08     9/11/08     N
                                      2 9/11/08     9/10/08     Y
                                      3 9/12/08     9/12/08     Y