create table #t(F_BeginDate datetime,
F_LastDay int,
F_Flag as case when getdate() between F_BeginDate and dateadd(d,F_LastDay,F_BeginDate) then 0 else 1 end
)
insert #t(F_BeginDate,F_LastDay) select '2006-12-01',20
Go
insert #t(F_BeginDate,F_LastDay) select '2006-12-01',30
Go
/* 但是mysql中没有计算列,所以你只能通过视图来实现了 */
alter view v_test
as
select F_BeginDate,
F_LastDay,
IF(sysdate() between F_BeginDate and F_BeginDate+interval F_LastDay Day,0,1) as F_Flag
from t;