重复值，我使用的是SQL Server 2008中我有一个表如何找到在SQL Server
Customers
customer_number int
field1 varchar
field2 varchar
field3 varchar
field4 varchar
...和更大量列，不为我的查询关系。
Column customer_number is pk。我试图找到重复的值和它们之间的一些差异。
请帮我找到有相同
1）字段1，字段2，字段3的所有行，字段4
2）只有3列是相等的，其中之一是不（除了来自列表1行）
3）只有2列相等，并且其中的两个是不（除了来自列表1和表2）
行最后，我将得到3个表，其中包含此结果和其他groupId，对于一组相似的结果将是相同的（例如，对于3列等于，具有相同列的3个行将等于一个单独的组）
谢谢。
最简单的做法可能是编写一个存储过程，对每组客户重复进行重复操作，并分别为每个组编号插入匹配的过程。
不过，我已经想过了，你可以用子查询来做到这一点。希望我没有把它变得比它应该更复杂，但是这应该让你找到你想要的第一张重复表格（全部四个字段）。请注意，这是未经测试的，所以可能需要稍微调整。
基本上，它会获取每组字段，其中有重复的每个组的编号，然后获取所有客户的这些字段并分配相同的组编号。
INSERT INTO FourFieldsDuplicates(group_no, customer_no)
SELECT Groups.group_no, custs.customer_no
FROM (SELECT ROW_NUMBER() OVER(ORDER BY c.field1) AS group_no,
c.field1, c.field2, c.field3, c.field4
FROM Customers c
GROUP BY c.field1, c.field2, c.field3, c.field4
HAVING COUNT(*) > 1) Groups
INNER JOIN Customers custs ON custs.field1 = Groups.field1
AND custs.field2 = Groups.field2
AND custs.field3 = Groups.field3
AND custs.field4 = Groups.field4
其他的更复杂一点，但是你需要扩大可能性。这三个字段组然后是：
INSERT INTO ThreeFieldsDuplicates(group_no, customer_no)
SELECT Groups.group_no, custs.customer_no
FROM (SELECT ROW_NUMBER() OVER(ORDER BY GroupsInner.field1) AS group_no,
GroupsInner.field1, GroupsInner.field2,
GroupsInner.field3, GroupsInner.field4
FROM (SELECT c.field1, c.field2, c.field3, NULL AS field4
FROM Customers c
WHERE NOT EXISTS(SELECT d.customer_no
FROM FourFieldsDuplicates d
WHERE d.customer_no = c.customer_no)
GROUP BY c.field1, c.field2, c.field3
UNION ALL
SELECT c.field1, c.field2, NULL AS field3, c.field4
FROM Customers c
WHERE NOT EXISTS(SELECT d.customer_no
FROM FourFieldsDuplicates d
WHERE d.customer_no = c.customer_no)
GROUP BY c.field1, c.field2, c.field4
UNION ALL
SELECT c.field1, NULL AS field2, c.field3, c.field4
FROM Customers c
WHERE NOT EXISTS(SELECT d.customer_no
FROM FourFieldsDuplicates d
WHERE d.customer_no = c.customer_no)
GROUP BY c.field1, c.field3, c.field4
UNION ALL
SELECT NULL AS field1, c.field2, c.field3, c.field4
FROM Customers c
WHERE NOT EXISTS(SELECT d.customer_no
FROM FourFieldsDuplicates d
WHERE d.customer_no = c.customer_no)
GROUP BY c.field2, c.field3, c.field4) GroupsInner
GROUP BY GroupsInner.field1, GroupsInner.field2,
GroupsInner.field3, GroupsInner.field4
HAVING COUNT(*) > 1) Groups
INNER JOIN Customers custs ON (Groups.field1 IS NULL OR custs.field1 = Groups.field1)
AND (Groups.field2 IS NULL OR custs.field2 = Groups.field2)
AND (Groups.field3 IS NULL OR custs.field3 = Groups.field3)
AND (Groups.field4 IS NULL OR custs.field4 = Groups.field4)
希望这会产生正确的结果，我将离开最后一个作为练习。 :-D
我不确定您是否需要在不同字段（如field1 = field2）上进行相等性检查。
否则这可能就够了。
编辑
随意调整TESTDATA向我们提供，让根据您的规格错误的输出输入。
测试数据
DECLARE @Customers TABLE (
customer_number INTEGER IDENTITY(1, 1)
, field1 INTEGER
, field2 INTEGER
, field3 INTEGER
, field4 INTEGER)
INSERT INTO @Customers
SELECT 1, 1, 1, 1
UNION ALL SELECT 1, 1, 1, 1
UNION ALL SELECT 1, 1, 1, NULL
UNION ALL SELECT 1, 1, 1, 2
UNION ALL SELECT 1, 1, 1, 3
UNION ALL SELECT 2, 1, 1, 1
人人平等
SELECT ROW_NUMBER() OVER (ORDER BY c1.customer_number)
, c1.field1
, c1.field2
, c1.field3
, c1.field4
FROM @Customers c1
INNER JOIN @Customers c2 ON c2.customer_number > c1.customer_number
AND ISNULL(c2.field1, 0) = ISNULL(c1.field1, 0)
AND ISNULL(c2.field2, 0) = ISNULL(c1.field2, 0)
AND ISNULL(c2.field3, 0) = ISNULL(c1.field3, 0)
AND ISNULL(c2.field4, 0) = ISNULL(c1.field4, 0)
一个不同领域的
SELECT ROW_NUMBER() OVER (ORDER BY field1, field2, field3, field4)
, field1
, field2
, field3
, field4
FROM (
SELECT DISTINCT c1.field1
, c1.field2
, c1.field3
, field4 = NULL
FROM @Customers c1
INNER JOIN @Customers c2 ON c2.customer_number > c1.customer_number
AND c2.field1 = c1.field1
AND c2.field2 = c1.field2
AND c2.field3 = c1.field3
AND ISNULL(c2.field4, 0) <> ISNULL(c1.field4, 0)
UNION ALL
SELECT DISTINCT c1.field1
, c1.field2
, NULL
, c1.field4
FROM @Customers c1
INNER JOIN @Customers c2 ON c2.customer_number > c1.customer_number
AND c2.field1 = c1.field1
AND c2.field2 = c1.field2
AND ISNULL(c2.field3, 0) <> ISNULL(c1.field3, 0)
AND c2.field4 = c1.field4
UNION ALL
SELECT DISTINCT c1.field1
, NULL
, c1.field3
, c1.field4
FROM @Customers c1
INNER JOIN @Customers c2 ON c2.customer_number > c1.customer_number
AND c2.field1 = c1.field1
AND ISNULL(c2.field2, 0) <> ISNULL(c1.field2, 0)
AND c2.field3 = c1.field3
AND c2.field4 = c1.field4
UNION ALL
SELECT DISTINCT NULL
, c1.field2
, c1.field3
, c1.field4
FROM @Customers c1
INNER JOIN @Customers c2 ON c2.customer_number > c1.customer_number
AND ISNULL(c2.field1, 0) <> ISNULL(c1.field1, 0)
AND c2.field2 = c1.field2
AND c2.field3 = c1.field3
AND c2.field4 = c1.field4
) c
这里有一个方便的q用于查找表中的重复项。假设你想找到存在一次以上表中的所有电子邮件地址：
SELECT email, COUNT(email) AS NumOccurrences
FROM users
GROUP BY email
HAVING (COUNT(email) > 1)
您也可以使用这种技术来发现出现一次行：
SELECT email
FROM users
GROUP BY email
HAVING (COUNT(email) = 1)
你可以写简单的东西这样算重复条目，我认为它的工作：
use *DATABASE_NAME*
go
SELECT *YOUR_FIELD*, COUNT(*) AS dupes
FROM *YOUR_TABLE_NAME*
GROUP BY *YOUR_FIELD*
HAVING (COUNT(*) > 1)
享受
上面的答案重复 – 2013-09-10 10:01:52
没有与CUBE()这样做的清洁方式，这将是所有可能的组合列
SELECT
field1,field2,field3,field4
,duplicate_row_count = COUNT(*)
,grp_id = GROUPING_ID(field1,field2,field3,field4)
INTO #duplicate_rows
FROM table_name
GROUP BY CUBE(field1,field2,field3,field4)
HAVING COUNT(*) > 1
AND GROUPING_ID(field1,field2,field3,field4) IN (0,1,2,4,8,3,5,6,9,10,12)
的数字（0,1,2,4,8,3,5,6聚集， 9,10,12）只是我们关心的分组集合的位掩码（0000,0001,0010,0100，...，1010,1100） - 那些有4,3或2个匹配的分组集合。
然后加入使用，在#duplicate_rows将NULL作为通配符
SELECT a.*
FROM table_name a
INNER JOIN #duplicate_rows b
ON NULLIF(b.field1,a.field1) IS NULL
AND NULLIF(b.field2,a.field2) IS NULL
AND NULLIF(b.field3,a.field3) IS NULL
AND NULLIF(b.field4,a.field4) IS NULL
--WHERE grp_id IN (0) --Use this for 4 matches
--WHERE grp_id IN (1,2,4,8) --Use this for 3 matches
--WHERE grp_id IN (3,5,6,9,10,12) --Use this for 2 matches
@Ic是不是写“c.field1为group_no”的技术，这回原来的表？ group_no是int，field1是varchar。 也许我应该使用一些临时表？ – hgulyan 2010-05-20 10:18:57
@hgulyan它实际上是ROW_NUMBER（）作为group_no。 – 2010-05-20 10:25:48
@Ic，是的，我已经改变了。仍然试图运行第一个脚本... – hgulyan 2010-05-20 10:27:49