同一个表中排除相同的同一个人（身份证有15位和18位）

select * from
(select name,idcard,city ,DepartName,substring(idcard,7,9) id1 ,substring(idcard,1,6) part1 from [Constable] where len(idcard)=15) a1
inner join
(select name,idcard,city,DepartName ,substring(idcard,9,9) id2,substring(idcard,1,6) part2 from [Constable] where len(idcard)=18) a2
on (a1.id1=a2.id2 and a1.part1 =a2.part2);