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去重復sql

發布時間: 2022-04-03 17:32:37

1. sql去除重復的項

  • 假設存在一個主鍵ID,Name為重復列,下面這句可以查出所有的沒有重復的數據:

  • select * from 表 as a where ID=(select min(ID) from 表 where Name=a.Name) 。

  • 根據上面這句就可以刪除所有重復項的數據:

  • delete from 表 where ID not in(select ID from 表 as a where ID=(select min(ID) from 表 where Name=a.Name))。

2. SQL查詢,如何去除重復的記錄

首先,先說明一個問題。這樣的結果出現,說明系統設計是有問題的。

其次
刪除重復數據,你要提供你是什麼資料庫
不同資料庫會有不同的解決方案。

關鍵字Distinct 去除重復,如下列SQL,去除Test相同的記錄;
1. select distinct Test from Table
2. 如果是要刪除表中存在的重復記錄,那就邏輯處理,如下:
3. select Test from Table group by Test having count(test)>1
4. 先查詢存在重復的數據,後面根據條件刪除

還有一個更簡單的方法可以嘗試一下:
select aid, count(distinct uid) from 表名 group by aid
這是sqlserver 的寫法。

  • 如圖一在數據表中有兩個膀胱沖洗重復的記錄。

3. SQL 怎麼去除完全重復的數據

用SQL語句,刪除掉重復項只保留一條

在幾千條記錄里,存在著些相同的記錄,如何能用SQL語句,刪除掉重復的呢
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)

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 peopleName in (select peopleName from people group by peopleName having count(peopleName) > 1)
and peopleId not in (select min(peopleId) from people group by peopleName having count(peopleName)>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)
6.消除一個欄位的左邊的第一位:
update tableName set [Title]=Right([Title],(len([Title])-1)) where Title like '村%'
7.消除一個欄位的右邊的第一位:
update tableName set [Title]=left([Title],(len([Title])-1)) where Title like '%村'
8.假刪除表中多餘的重復記錄(多個欄位),不包含rowid最小的記錄
update vitae set ispass=-1
where peopleId in (select peopleId from vitae group by peopleId

4. sql去除重復數據

測試這樣是可以的
select * from table where a in ( select a from table group by a having count(*)<2)

5. 求助SQL去除重復項

select distinct 欄位,欄位 from 表名
distinct 只能去掉 所有欄位都完全相同的數據,即使有一個不相同也不會去重

6. SQL語句 去除重復

select userid,min(username) username,groupid
from table_name
where userid=1
group by userid,groupid
order by 1,3

7. 求SQL消除重復數據語句

select * from #t1
union
select * from #t2
這條語句一起執行是把兩個表中唯一的查詢出來,如果用union all會把兩個表中的結果並集起來

8. sql語句,去重復,求和值

SELECT SUM(b) FROM (SELECT DISTINCT * FROM A)
對於表中兩行記錄完全一樣的情況,可以用下面語句獲取到去掉重復數據後的記錄:
select distinct * from 表名
將查詢的記錄放到臨時表中

9. 【sql去除重復數據】

select
DISTINCT finger,width,height,size,type
form image
order by finger,width,height,size,type

10. SQL查詢去除重復記錄

select distinct(*)
from 表名
where 職業="無業"

上邊distinct 就是去除重復的關鍵字