1.表中有id和name 两个字段，查询出name重复的全部数据sql
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1
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select
*
from
xi a
where
(a.username)
in
(
select
username
from
xi
group
by
username
having
count
(*) > 1)
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二、查询出全部数据进行分组以后，和重复数据的重复次数的查询数据，先列下：ide
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1
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select
count
(username)
as
'重复次数'
,username
from
xi
group
by
username
having
count
(*)>1
order
by
username
desc
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三、一下为 查看别人的 结果，现列下：查询及删除重复记录的方法大全fetch
一、查找表中多余的重复记录，重复记录是根据单个字段（peopleId）来判断spa
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2
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select
*
from
people
where
peopleId
in
(
select
peopleId
from
people
group
by
peopleId
having
count
(peopleId) > 1)
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二、删除表中多余的重复记录，重复记录是根据单个字段（peopleId）来判断，只留有rowid最小的记录.net
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3
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delete
from
people
where
peopleId
in
(
select
peopleId
from
people
group
by
peopleId
having
count
(peopleId) > 1)
and
rowid
not
in
(
select
min
(rowid)
from
people
group
by
peopleId
having
count
(peopleId )>1)
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三、查找表中多余的重复记录（多个字段）设计
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2
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select
*
from
vitae a
where
(a.peopleId,a.seq)
in
(
select
peopleId,seq
from
vitae
group
by
peopleId,seq
having
count
(*) > 1)
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四、删除表中多余的重复记录（多个字段），只留有rowid最小的记录code
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3
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delete
from
vitae a
where
(a.peopleId,a.seq)
in
(
select
peopleId,seq
from
vitae
group
by
peopleId,seq
having
count
(*) > 1)
and
rowid
not
in
(
select
min
(rowid)
from
vitae
group
by
peopleId,seq
having
count
(*)>1)
|
五、查找表中多余的重复记录（多个字段），不包含rowid最小的记录htm
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1
2
3
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select
*
from
vitae a
where
(a.peopleId,a.seq)
in
(
select
peopleId,seq
from
vitae
group
by
peopleId,seq
having
count
(*) > 1)
and
rowid
not
in
(
select
min
(rowid)
from
vitae
group
by
peopleId,seq
having
count
(*)>1)
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(二)索引
比方说ip
在A表中存在一个字段“name”，
并且不一样记录之间的“name”值有可能会相同，
如今就是须要查询出在该表中的各记录之间，“name”值存在重复的项；
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1
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Select
Name
,
Count
(*)
From
A
Group
By
Name
Having
Count
(*) > 1
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若是还查性别也相同大则以下:
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1
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Select
Name
,sex,
Count
(*)
From
A
Group
By
Name
,sex
Having
Count
(*) > 1
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(三)
方法一
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declare
@
max
integer
,@id
integer
declare
cur_rows
cursor
local
for
select
主字段,
count
(*)
from
表名
group
by
主字段
having
count
(*) >;
open
cur_rows
fetch
cur_rows
into
@id,@maxwhile @@fetch_status=0
begin
select
@
max
= @
max
-1
set
rowcount @
max
delete
from
表名
where
主字段 = @id
fetch
cur_rows
into
@id,@maxend
close
cur_rows
set
rowcount 0
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方法二＂重复记录＂有两个意义上的重复记录，一是彻底重复的记录，也即全部字段均重复的记录，二是部分关键字段重复的记录，好比Name字段重复，而其余字段不必定重复或都重复能够忽略。
一、对于第一种重复，比较容易解决，使用
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1
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select
distinct
*
from
tableName
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就能够获得无重复记录的结果集。
若是该表须要删除重复的记录（重复记录保留1条），
能够按如下方法删除
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3
4
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select
distinct
*
into
#Tmp
from
tableName
drop
table
tableName
select
*
into
tableName
from
#Tmp
drop
table
#Tmp
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发生这种重复的缘由是表设计不周产生的，增长惟一索引列便可解决。
二、这类重复问题一般要求保留重复记录中的第一条记录，操做方法以下 假设有重复的字段为Name,Address，要求获得这两个字段惟一的结果集
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3
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select
identity(
int
,1,1)
as
autoID, *
into
#Tmp
from
tableName
select
min
(autoID)
as
autoID
into
#Tmp2
from
#Tmp
group
by
Name
,autoID
select
*
from
#Tmp
where
autoID
in
(
select
autoID
from
#tmp2)
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最后一个select即获得了Name，Address不重复的结果集（但多了一个autoID字段，实际写时能够写在select子句中省去此列）
(四)查询重复
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1
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select
*
from
tablename
where
id
in
(
select
id
from
tablenamegroup
by
idhaving
count
(id) > 1)
|
对一个字段查找重复记录
根据sample_code字段找到重复记录
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1
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SELECT
*
FROM
tb_table
WHERE
sample_code
IN
(
SELECT
sample_code
FROM
tb_table
GROUP
BY
sample_code
HAVING
COUNT
(sample_code) > 1 );
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对多个字段查找重复记录（这里以2个为例）
根据name和code字段找到重复记录
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SELECT
*
from
(
SELECT
*, CONCAT(
name
,code)
as
nameAndCode
from
tb_table) t
WHERE
t.nameAndCode
in
(
SELECT
nameAndCode
from
(
SELECT
CONCAT(
name
,code)
as
nameAndCode
from
tb_table) tt
GROUP
BY
nameAndCode
HAVING
count
(nameAndCode) > 1
)
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多字段查，删
查
SELECT * FROM vip_goodsdiscount WHERE (goodsId,cardType) IN (SELECT goodsId,cardType FROM vip_goodsdiscount GROUP BY goodsId,cardType HAVING COUNT(*) > 1)
ORDER BY goodsId DESC
删
DELETE FROM vip_goodsdiscount WHERE (vip_goodsdiscount.goodsId,vip_goodsdiscount.cardType) IN (SELECT * FROM (SELECT goodsId,cardType FROM vip_goodsdiscount GROUP BY goodsId,cardType HAVING COUNT(*) > 1) AS t1 ) AND id NOT IN (SELECT * FROM (SELECT MIN(id) FROM vip_goodsdiscount GROUP BY goodsId,cardType HAVING COUNT(*)>1) AS t2)