使用一个字段很容易找到重复项：
SELECT email, COUNT(email)
FROM users
GROUP BY email
HAVING COUNT(email) > 1
所以如果我们有一张桌子
ID NAME EMAIL
1 John asd@asd.com
2 Sam asd@asd.com
3 Tom asd@asd.com
4 Bob bob@asd.com
5 Tom asd@asd.com
这个查询将告诉我们John、Sam、Tom和Tom，因为他们都有相同的电子邮件。
然而，我想要的是获得相同电子邮件和名称的副本。
也就是说，我想得到“汤姆”，“汤姆”。
我需要这个的原因是：我犯了一个错误，允许插入重复的名称和电子邮件值。现在我需要删除/更改重复项，所以我需要先找到它们。
当前回答
删除名称重复的记录
;WITH CTE AS
(
SELECT ROW_NUMBER() OVER (PARTITION BY name ORDER BY name) AS T FROM @YourTable
)
DELETE FROM CTE WHERE T > 1
其他回答
select name, email
, case
when ROW_NUMBER () over (partition by name, email order by name) > 1 then 'Yes'
else 'No'
end "duplicated ?"
from users
删除名称重复的记录
;WITH CTE AS
(
SELECT ROW_NUMBER() OVER (PARTITION BY name ORDER BY name) AS T FROM @YourTable
)
DELETE FROM CTE WHERE T > 1
另一种简单的方法是使用解析函数：
SELECT * from
(SELECT name, email,
COUNT(name) OVER (PARTITION BY name, email) cnt
FROM users)
WHERE cnt >1;
您使用我使用的以下查询：
select *
FROM TABLENAME
WHERE PrimaryCoumnID NOT IN
(
SELECT MAX(PrimaryCoumnID)
FROM TABLENAME
GROUP BY AnyCoumnID
);
select emp.ename, emp.empno, dept.loc
from emp
inner join dept
on dept.deptno=emp.deptno
inner join
(select ename, count(*) from
emp
group by ename, deptno
having count(*) > 1)
t on emp.ename=t.ename order by emp.ename
/
