create table Users
(
    [UserName] nvarchar(32) not null,
    [Sex] bit not null,
    [Age] int not null,
);

insert into Users values('王杰', 1, 40);
insert into Users values('王杰', 1, 40);
insert into Users values('王杰', 1, 40);
insert into Users values('苏有朋', 1, 40);
insert into Users values('苏有朋', 1, 40);
insert into Users values('刘德华', 1, 40);
insert into Users values('刘德华', 0, 40);

---先把符合条件记录放入一个临时表中，
select distinct UserName,Sex,Age   into #temp from Users

----然后把原表删除掉
  delete Users

----然后把临时表记录插入
insert into Users
select UserName,Sex,Age   from #temp

------解决方案--------------------
所有列都存在重复的话,需要借用临时表来实现.
SQL code
create table Users
(
    [UserName] nvarchar(32) not null,
    [Sex] bit not null,
    [Age] int not null,
);

insert into Users values('王杰', 1, 40);
insert into Users values('王杰', 1, 40);
insert into Users values('王杰', 1, 40);
insert into Users values('苏有朋', 1, 40);
insert into Users values('苏有朋', 1, 40);
insert into Users values('刘德华', 1, 40);
insert into Users values('刘德华', 0, 40);

go

select distinct * into tmp from users
truncate table users
insert into users select * from tmp
drop table tmp
select * from users
/*
UserName                         Sex  Age         
-------------------------------- ---- ----------- 
刘德华                              0    40
刘德华                              1    40
苏有朋                              1    40
王杰                               1    40

（所影响的行数为 4 行）
*/


drop table users

------解决方案--------------------
select username,sex,age from users group by username,sex,age

------解决方案--------------------

delete from (select run_number()over(order by username,sex,age) as odr  from users)a
where a.odr<>1


------解决方案--------------------
SQL code

create table Users
(
    [UserName] nvarchar(32) not null,
    [Sex] bit not null,
    [Age] int not null,
);

insert into Users values('王杰', 1, 40);
insert into Users values('王杰', 1, 40);
insert into Users values('王杰', 1, 40);
insert into Users values('苏有朋', 1, 40);
insert into Users values('苏有朋', 1, 40);
insert into Users values('刘德华', 1, 40);
insert into Users values('刘德华', 0, 40);

;with _a as(
    select row_number()over(partition by username,sex,age order by username) as coou,* from users
)

select username,sex,age from _a where coou=1

------解决方案--------------------
SQL code

-- 查出数据插入新表
select [UserName],[sex],[age] from (
    select 
    r=row_number() over (partition by [UserName],[sex],[age] order by newid()),*
    from users
) a where a.r=1
-- 删除旧表，新表.表名 = 旧表.表名

------解决方案--------------------
SQL code
--删除重复记录
--1),
delete from tablename where id not in (select max(id) from tablename group by col1,col2,...)
--2),
select distinct * into temp from tablename
delete from tablename
insert into tablename select * from temp