declare @a表 table (id int,col2 int,col3 int,col4 int)
insert into @a表
select 1,1,7,2 union all
select 2,2,4,1 union all
select 3,2,4,1

declare @b表 table (id int,col2 int,col3 int,col4 int)
insert into @b表
select 1,2,4,1 union all
select 2,3,4,2 union all
select 3,1,7,9

select distinct col2,col3,col4,
表内重复行数=(select count(1)-1 from @a表 where a.col2=col2 and a.col3=col3 and a.col4=col4),
表外重复行数=(select count(1) from @b表 where a.col2=col2 and a.col3=col3 and a.col4=col4)
from @a表 a
where 
(select count(1)-1 from @a表 where a.col2=col2 and a.col3=col3 and a.col4=col4)>0
or
(select count(1) from @b表 where a.col2=col2 and a.col3=col3 and a.col4=col4)>0

/*
col2        col3        col4        表内重复行数      表外重复行数
----------- ----------- ----------- ----------- -----------
2           4           1           1           1
*/