Question

所以我有一个数据库，行数超过2000行，我想删除基于2行的重复值。

例如：

no     server     name
1      serv1       a
2      serv1       b
3      serv1       b
4      serv1       b
5      serv2       a
6      serv2       b
7      serv2       c
8      serv2       c

所以基本上我想删除重复的 IF 其中两行重复的
但我不想删除它们，如果只是其中一行有重复。

预期输出：

no      server     name
1       serv1       a
2       serv1       b
3       serv2       a
4       serv2       b
5       serv2       c

任何答案将不胜感激。

Answer 1

使用select distinct：

select distinct server, name
from t;

如果重复很多，最简单的方法可能是重新创建表：

create table temp_t as
    select min(no) as no, server, name
    from t
    group by server, name;

truncate table t;

insert into t (no, server, name)
    select no, server, name
    from temp_t;

如果您没有很多行，那么delete可以：

delete t
    from t join
         (select server, name, min(no) as min_no
          from t
          group by server, name
         ) tt
         on t.server = tt.server and t.name = tt.name
    where t.no > tt.min_no;

Answer 2

有很多方法可以做您想要的。如果您只是在寻找SELECT没有重复的数据，则可以使用：

DISTINCT

SELECT DISTINCT Server,
                Name
FROM YourTableName

组别

SELECT Server,
       Name
FROM YourTableName
GROUP BY Server, Name

子查询中的窗口函数（ROW_NUMBER）

SELECT Server, 
       Name
FROM
(
  SELECT *,
         ROW_NUMBER() OVER(PARTITION BY Server, Name ORDER BY Server) RN
  FROM YourTableName
) TT
WHERE TT.RN = 1

您将重复项删除为

DELETE T1
FROM
(
  SELECT ROW_NUMBER() OVER(PARTITION BY Server, Name ORDER BY Server) RN
  FROM T --YourTableName
) T1 JOIN
(
  SELECT ROW_NUMBER() OVER(PARTITION BY Server, Name ORDER BY Server) RN
  FROM T --YourTableName
) T2 ON T1.RN = T2.RN
WHERE T1.RN > 1;

Answer 3

您可以使用以下查询删除重复项

DELETE t1 FROM tablename t1 INNER JOIN tablename t2 
WHERE t1.id < t2.id AND t1.server = t2.server AND t1.name = t2.name;

根据2行值删除重复项

3 个答案: