MYSQL 查找出重复列值

Question

DB: MySqlProblem:create table aaa(
    id int primary key,
    phone varchar(100),
    name varchar(50)
)insert into aaa values(000101,'111','jackie');
insert into aaa values(000102,'222','milk');
insert into aaa values(000103,'111','lucy');
insert into aaa values(000104,'111','mechelle');
insert into aaa values(000105,'222','tom');
insert into aaa values(000106,'333','roy');查找出phone列有重复的值，即count(phone)>=2的值列出来Required Result:
phone   num
111     3
222     2请高手解答，在线等，谢谢

Answer 1

select phone,
       count(*)num
from aaa
group by phone
having count(*)>=2

Answer 2

create table aaa(
  id int primary key,
  phone varchar(100),
  name varchar(50)
)insert into aaa values(000101,'111','jackie');
insert into aaa values(000102,'222','milk');
insert into aaa values(000103,'111','lucy');
insert into aaa values(000104,'111','mechelle');
insert into aaa values(000105,'222','tom');
insert into aaa values(000106,'333','roy');
select phone,
       count(*)num
from aaa
group by phone
having count(*)>=2
drop table aaa
/*
phone                                                                                                num
---------------------------------------------------------------------------------------------------- -----------
111                                                                                                  3
222                                                                                                  2(2 個資料列受到影響)
*/

Answer 3

select phone,count(phone) as num from aaa
group by phone
having count(phone)>=2

Answer 4

select phone, count(*)num from aaa
group by phone
having count(phone)>=2