insert into 表B 
    select A,B,C,D from 表A a where 日期='2012-5-19'
        and not exists (select 1 from 表B b
            where a.A=b.A and a.B=b.B and a.C=b.C and a.D=b.D)

------解决方案--------------------
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SQL code

insert into 表B
select A,B,C,D from 表A a where 日期='2012-5-19'
and not exists (select 1 from 表B b
where a.A=b.A and a.B=b.B and a.C=b.C and a.D=b.D)


如果日期改为系统时间的每天早上9点请问该……


------解决方案--------------------
insert into 表B
select A,B,C,D from 表A a where 日期='2012-5-19'
and a.A not in (select a from B)即可肯定有一个主键的


------解决方案--------------------
select a.a,a.b,a.c,a.d into tbB from A a
where 日期=‘’