Find repeating values from table

Today i am going to discuss a very common problem that takes too much time of developers to write code and find soution

Problem: How can i find duplicate and return values from table data
Solution: Using SQL Server following is the example to find duplicating values.


create table repeatCheck
(id int identity(1,1),
email varchar(50));

insert into repeatCheck values ('shamas@isl.com');
insert into repeatCheck values ('shamas@isl.com');
insert into repeatCheck values ('maria@isl.com');
insert into repeatCheck values ('azher@isl.com');
insert into repeatCheck values ('khawar@isl.com');
insert into repeatCheck values ('khalil@isl.com');
insert into repeatCheck values ('maria@isl.com');


select * from repeatCheck

--- Now return all repeating emails

select email,count(email) as emailcount
from repeatCheck
group by email
having count(email) > 1


As you can see how simple is to return duplicate values for different email addresses