有沒有什麼腳本可以刪除重復項
1. SQL重復記錄查詢 查詢多個欄位、多表查詢、刪除重復記錄的方法
SQL重復記錄查詢
1、查找表中多餘的重復記錄，重復記錄是根據單個欄位（peopleId）來判斷
select
*
from
people
where
peopleId
in
(select
peopleId
from
people
group
by
peopleId
having
count(peopleId)
>
1)
例二：
select
*
from
testtable
where
numeber
in
(select
number
from
people
group
by
number
having
count(number)
>
1
)
可以查出testtable表中number相同的記錄
2、刪除表中多餘的重復記錄，重復記錄是根據單個欄位（peopleId）來判斷，只留有rowid最小的記錄
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)
3、查找表中多餘的重復記錄（多個欄位）
select
*
from
vitae
a
where
(a.peopleId,a.seq)
in
(select
peopleId,seq
from
vitae
group
by
peopleId,seq
having
count(*)
>
1)
4、刪除表中多餘的重復記錄（多個欄位），只留有rowid最小的記錄
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)
5、查找表中多餘的重復記錄（多個欄位），不包含rowid最小的記錄
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)
(二)
比方說
在A表中存在一個欄位「name」，
而且不同記錄之間的「name」值有可能會相同，
現在就是需要查詢出在該表中的各記錄之間，「name」值存在重復的項；
Select
Name,Count(*)
From
A
Group
By
Name
Having
Count(*)
>
1
如果還查性別也相同大則如下：
Select
Name,sex,Count(*)
From
A
Group
By
Name,sex
Having
Count(*)
>
1
(三)
方法一
declare
@max
integer,@id
integer
declare
cur_rows
cursor
local
for
select
主欄位,count(*)
from
表名
group
by
主欄位
having
count(*)
>；
1
open
cur_rows
fetch
cur_rows
into
@id,@max
while
@@fetch_status=0
begin
select
@max
=
@max
-1
set
rowcount
@max
delete
from
表名
where
主欄位
=
@id
fetch
cur_rows
into
@id,@max
end
close
cur_rows
set
rowcount
0
方法二
有兩個意義上的重復記錄，一是完全重復的記錄，也即所有欄位均重復的記錄，二是部分關鍵欄位重復的記錄，比如Name欄位重復，而其他欄位不一定重復或都重復可以忽略。
1、對於第一種重復，比較容易解決，使用
select
distinct
*
from
tableName
就可以得到無重復記錄的結果集。
如果該表需要刪除重復的記錄（重復記錄保留1條），可以按以下方法刪除
select
distinct
*
into
#Tmp
from
tableName
drop
table
tableName
select
*
into
tableName
from
#Tmp
drop
table
#Tmp
發生這種重復的原因是表設計不周產生的，增加唯一索引列即可解決。
2、這類重復問題通常要求保留重復記錄中的第一條記錄，操作方法如下
假設有重復的欄位為Name,Address，要求得到這兩個欄位唯一的結果集
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)
最後一個select即得到了Name，Address不重復的結果集（但多了一個autoID欄位，實際寫時可以寫在select子句中省去此列）
(四)
查詢重復
select
*
from
tablename
where
id
in
(
select
id
from
tablename
group
by
id
having
count(id)
>
1
)
以上就是小編為大家帶來的SQL重復記錄查詢
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