Question

我有一张如下表格

1,1@email.com,null
2,1@email.com,systemID2
3,2@email.com,null
4,2@email.com,null
5,3@email.com,systemID3
6,1@email.com,null

该表格中包含重复的电子邮件地址。在这些重复项中，有些具有＆＃39; systemID＆＃39; 我想要查询没有SystemID的所有重复项（只要其中一个重复项具有SystemID）

在此示例中，查询应仅提供两个结果：

1,1@email.com,null
6,1@email.com,null

Answer 1

试试这个：

use tempdb

create table temp(
    id int,
    email varchar(100),
    systemId varchar(100)
)
insert into temp
select 1,'1@email.com',null union  all
select 2,'1@email.com','systemID2' union  all
select 3,'2@email.com',null union  all
select 4,'2@email.com',null union  all
select 5,'3@email.com','systemID3' union  all
select 6,'1@email.com',null

;with cte as(
    select
        *,
        cc = count(*) over(partition by email)
    from temp
)
select 
    t.*
from temp t
inner join cte c
    on c.email = t.email
    and c.cc > 1
    and c.systemId is not null
where
    t.systemId is null
order by email

drop table temp

Answer 2

试试这个。

;WITH cte
     AS (SELECT Count(1) cnt,a.email
         FROM   tablename a
                JOIN tablename b
                  ON a.email = b.email
         WHERE  a.systemId IS NOT NULL
         GROUP  BY a.email
         HAVING( Count(1) ) > 1)
SELECT b.id,b.email,b.systemId
FROM   cte a
       JOIN tablename b
         ON a.email = b.email
WHERE  b.systemId IS NULL

根据systemID，主键和电子邮件删除重复项

2 个答案: