是数据库里，还是excel文件中？

是数据库里。数据比比较大，而且event没有规律。求指教

帮你顶一下吧，想了蛮久也没想出来。。

ORACLE：

create table TEST
(
  dt    DATE not null,
  event NUMBER(2) not null,
  y     NUMBER(2)
)
建表后，自己随便整点数据

  select *
    from test
   where dt - 2 in (select DT from Test where event > 0)
      or dt - 1 in (select DT from Test where event > 0)
      or dt in (select DT from Test where event > 0)
      or dt + 1 in (select DT from Test where event > 0)
      or dt + 2 in (select DT from Test where event > 0)

更新y值：
update test set y=1
   where dt - 2 in (select DT from Test where event > 0)
      or dt - 1 in (select DT from Test where event > 0)
      or dt in (select DT from Test where event > 0)
      or dt + 1 in (select DT from Test where event > 0)
      or dt + 2 in (select DT from Test where event > 0)
数据量大的话，效率比较低，最好拆成5个update：
update test set y=1  where dt - 2 in (select DT from Test where event > 0)
update test set y=1  where dt -1 in (select DT from Test where event > 0)
update test set y=1  where dt in (select DT from Test where event > 0)
update test set y=1  where dt +1 in (select DT from Test where event > 0)
update test set y=1  where dt +2 in (select DT from Test where event > 0)

最后记得commit

你最好现执行查询语句，看看选出的结果集是不是你要更新的