数据库的统计问题

[danmali]

现在有4个数据表a,b,c,d，表中都含有 tel 字段！要统计4个表中tel字段所有重复的值，并列出来，sql语言怎么写？（我想知道用什么方法能先把4个表中的tel字段的数据先汇总起来，是用视图吗？）请老鸟们帮帮忙！

[gmlxf]

汇总union all:

select tel from a
union all
select tel from b
union all
select tel from c
union all
select tel from d

[gmlxf]

具有重复的tel：

select tel from
(select tel from a
union all
select tel from b
union all
select tel from c
union all
select tel from d
) a group by tel having count(*)>1

[victorycyz]

用楼上的方法：
select tel
from
( select tel from a
union all
select tel from b
union all
select tel from c
union all
select tel from d
) a
group by tel
having count(*)>1

[victorycyz]

不好意思，雷同了。我回贴的时候只看到了一楼的回贴的。

[LoveSQL]

select tel
from
( select tel from a
union all
select tel from b
union all
select tel from c
union all
select tel from d
) a
group by tel
having count(*)>1