⑴ sql如何排除多欄位的重復項
--sqlser代碼
select*from
(
select*,row_number()over(partitionby[名稱],[顏色]orderby[時間]asc)asgroup_idxfromtablename
)k
wheregroup_idx=1
⑵ SQL多個欄位如何去重
SQL語句為:select distinct telephone (屬性) from test(表名)
因為號碼有重復,所以以號碼telephone來查詢,配合distinct,使得查詢結果不重復。
使用關鍵字:distinct即可去重。
(2)sql多個欄位重復擴展閱讀:
選擇列表(select_list)指出所查詢列,它可以是一組列名列表、星號、表達式、變數(包括局部變數和全局變數)等構成。
1、選擇所有列
例如,下面語句顯示testtable表中所有列的數據:
SELECT *FROM testtable
2、選擇部分列並指定它們的顯示次序
查詢結果集合中數據的排列順序與選擇列表中所指定的列名排列順序相同。
3、更改列標題
在選擇列表中,可重新指定列標題。定義格式為:
列標題=列名列名 列標題
如果指定的列標題不是標準的標識符格式時,應使用引號定界符,例如,下列語句使用漢字顯示列標題:SELECT 昵稱=nickname,電子郵件=emailFROM testtable。
4、刪除重復行
SELECT語句中使用ALL或DISTINCT選項來顯示表中符合條件的所有行或刪除其中重復的數據行,默認為ALL。使用DISTINCT選項時,對於所有重復的數據行在SELECT返回的結果集合中只保留一行。
5、限制返回的行數
使用TOP n [PERCENT]選項限制返回的數據行數,TOP n說明返回n行,而TOP n PERCENT時,說明n是表示一百分數,指定返回的行數等於總行數的百分之幾。TOP命令僅針對SQL Server系列資料庫,並不支持Oracle資料庫。
⑶ 怎麼在sql中查找多個欄位數據相同
可用group by……having來實現。
可做如下測試:
1、創建表插入數據:
1
2
3
4
5
6
7
8
9
create table test
(id int,
name varchar(10))
insert into test values (1,'張三')
insert into test values (2,'李四')
insert into test values (3,'張三')
insert into test values (4,'王五')
insert into test values (5,'趙六')
其中name是張三的有兩行,也就是重復行。
2、執行sql語句如下:
1
2
select * from test where name in
(select name from test group by name having COUNT(*)>1)
結果如圖:
⑷ SQL查詢中如何剔除重復
1,存在兩條完全相同的紀錄
這是最簡單的一種情況,用關鍵字distinct就可以去掉
example: select distinct * from table(表名) where (條件)
2,存在部分欄位相同的紀錄(有主鍵id即唯一鍵)
如果是這種情況的話用distinct是過濾不了的,這就要用到主鍵id的唯一性特點及group by分組
example:
select * from table where id in (select max(id) from table group by [去除重復的欄位名列表,....])
3,沒有唯一鍵ID
example:
select identity(int1,1) as id,* into newtable(臨時表) from table
select * from newtable where id in (select max(id) from newtable group by [去除重復的欄位名列表,....])
drop table newtable
(4)sql多個欄位重復擴展閱讀
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 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)
⑸ SQL查詢,如何去除重復的記錄
sql查詢去除重復值語句x0dx0asql 單表/多表查詢去除重復記錄x0dx0a單表distinctx0dx0ax0dx0a多表group byx0dx0ax0dx0agroup by 必須放在 order by 和 limit之前,不然會報錯x0dx0ax0dx0a************************************************************************************x0dx0ax0dx0a1、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x0dx0ax0dx0aselect * from peoplex0dx0ax0dx0awhere peopleId in (select peopleId from people group by peopleId having count(peopleId) > 1)x0dx0a2、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x0dx0ax0dx0adelete from peoplex0dx0awhere peopleId in (select peopleId from people group by peopleId having count(peopleId) > 1)x0dx0aand rowid not in (select min(rowid) from people group by peopleId having count(peopleId )>1)x0dx0a3、查找表中多餘的重復記錄(多個欄位)x0dx0ax0dx0aselect * from vitae ax0dx0awhere (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having count(*) > 1)x0dx0a4、刪除表中多餘的重復記錄(多個欄位),只留有rowid最小的記錄x0dx0adelete from vitae ax0dx0awhere (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having count(*) > 1)x0dx0aand rowid not in (select min(rowid) from vitae group by peopleId,seq having count(*)>1)x0dx0a5、查找表中多餘的重復記錄(多個欄位),不包含rowid最小的記錄x0dx0ax0dx0aselect * from vitae ax0dx0awhere (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having count(*) > 1)x0dx0aand rowid not in (select min(rowid) from vitae group by peopleId,seq having count(*)>
⑹ sql怎麼查詢兩個欄位相同的記錄
1、查詢重復的數據,只查詢重復記錄,不管其餘信息,如ID什麼的:
1selectuid,timefromztestGROUPBYuid,timehavingcount(*)>1;
查出結果讓春是
uid time
1 1