Question

最顶上结果为什么多查询出一条?

select 1 as flag,bh,gm,wjm,yz,gx,bb from t1 where not exists (select 1
from t2 where t1.bc=t2.bc and
t1.yc=t2.yc and
t1.gm=t2.gm and
t1.yz=t2.yz and
t1.gx=t2.gx and
t1.zt=t2.zt and
t1.bb=t2.bb and
t1.wjm=t2.wjm and
t1.xg=t2.xg)
union all
select 0 as flag,bh,gm,wjm,yz,gx,bb from t2 where not exists(select 1
from t1 where t1.bc=t2.bc and
t1.yc=t2.yc and
t1.gm=t2.gm and
t1.yz=t2.yz and
t1.gx=t2.gx and
t1.zt=t2.zt and
t1.bb=t2.bb and
t1.wjm=t2.wjm and
t1.xg=t2.xg)
xg是时间类型！！！！！！！！！！！！！！！！！！！

Answer 1

你是说“阿杜” 那条吗？如果是的话，那是因为你用union all导致的！