选择条件-Sql server

Question

我有一个表test，如下所示

Contract   date_prolog    hours 
-------------------------------
No                         20
Yes         24/02/2014     10
No                         30
No                         10

如何获得此结果？

Contract   date_prolog    hours 
-------------------------------
No          24/02/2014     20
No          24/02/2014     30
No          24/02/2014     10

Answer 1

select contract, 
       (select date_prolog from test where contract = 'yes') as date_prolog, 
       hours
from test
where contract = 'no'