我有一个组织的SQL Server数据库,有许多重复的行。我想运行一个选择语句来获取所有这些和被欺骗的数量,同时还返回与每个组织相关的id。
这样的陈述:
SELECT orgName, COUNT(*) AS dupes
FROM organizations
GROUP BY orgName
HAVING (COUNT(*) > 1)
将返回如下内容
orgName | dupes
ABC Corp | 7
Foo Federation | 5
Widget Company | 2
但我也想要他们的id。有什么办法可以做到吗?也许就像
orgName | dupeCount | id
ABC Corp | 1 | 34
ABC Corp | 2 | 5
...
Widget Company | 1 | 10
Widget Company | 2 | 2
原因是还有一个单独的用户表链接到这些组织,我想把它们统一起来(因此删除dupes,用户链接到同一个组织,而不是dupe组织)。但我想手动部分,所以我不会搞砸任何事情,但我仍然需要一个语句返回所有的dupe组织的id,这样我就可以通过用户列表。
select * from [Employees]
查找重复记录
1)使用CTE
with mycte
as
(
select Name,EmailId,ROW_NUMBER() over(partition by Name,EmailId order by id) as Duplicate from [Employees]
)
select * from mycte
2)使用GroupBy
select Name,EmailId,COUNT(name) as Duplicate from [Employees] group by Name,EmailId
有几种方法可以选择重复的行。
对于我的解决方案,首先考虑以下表格为例
CREATE TABLE #Employee
(
ID INT,
FIRST_NAME NVARCHAR(100),
LAST_NAME NVARCHAR(300)
)
INSERT INTO #Employee VALUES ( 1, 'Ardalan', 'Shahgholi' );
INSERT INTO #Employee VALUES ( 2, 'name1', 'lname1' );
INSERT INTO #Employee VALUES ( 3, 'name2', 'lname2' );
INSERT INTO #Employee VALUES ( 2, 'name1', 'lname1' );
INSERT INTO #Employee VALUES ( 3, 'name2', 'lname2' );
INSERT INTO #Employee VALUES ( 4, 'name3', 'lname3' );
第一个解决方案:
SELECT DISTINCT *
FROM #Employee;
WITH #DeleteEmployee AS (
SELECT ROW_NUMBER()
OVER(PARTITION BY ID, First_Name, Last_Name ORDER BY ID) AS
RNUM
FROM #Employee
)
SELECT *
FROM #DeleteEmployee
WHERE RNUM > 1
SELECT DISTINCT *
FROM #Employee
第二个解决方案:使用标识字段
SELECT DISTINCT *
FROM #Employee;
ALTER TABLE #Employee ADD UNIQ_ID INT IDENTITY(1, 1)
SELECT *
FROM #Employee
WHERE UNIQ_ID < (
SELECT MAX(UNIQ_ID)
FROM #Employee a2
WHERE #Employee.ID = a2.ID
AND #Employee.FIRST_NAME = a2.FIRST_NAME
AND #Employee.LAST_NAME = a2.LAST_NAME
)
ALTER TABLE #Employee DROP COLUMN UNIQ_ID
SELECT DISTINCT *
FROM #Employee
所有解决方案的最后使用这个命令
DROP TABLE #Employee