Question

我有一张如下表格

CompanyNumber   Name  Status     other column1    other Column2
     10           A     Active
     10           A      NULL
     11           B     Active
     11           B       NULL
     12           C     Active
     12           C        NULL
     13           D        NULL
     14           E      Active


     ...

这样超过30万行。

我想删除状态为NULL的那个，结果表应如下所示：

      CompanyNumber    Name    Status
         10              A       Active
         11              B       Active
         12              C       Active
         13              D       NULL
         14              E       Active

Answer 1

我知道你要删除status为null的行。尝试使用where子句的SQL，如

DELETE
FROM mytable
WHERE status is null

如果您只想删除重复的行，那么您可以执行以下操作：

DELETE
FROM mytable
WHERE status is null
AND CompanyNumber  IN (SELECT CompanyNumber 
                       FROM mytable
                       GROUP BY CompanyNumber 
                       HAVING COUNT(CompanyNumber) > 1)

Answer 2

;WITH CTE AS 
( 
 SELECT CompanyNumber
      ,Name 
      ,[Status]
      ,ROW_NUMBER() OVER (PARTITION BY CompanyNumber, Name ORDER BY [Status] DESC) rn 
 FROM @TABLE
)
DELETE FROM CTE WHERE rn > 1

Answer 3

如果您想保留第一条记录并删除其他重复记录，请检查此...

   select *,
row_number() over  (partition by CompanyNumber   order by CompanyNumber)as rno 
into  #temp  from table 

  delete * from 
  table 
 where CompanyNumber in
 (select CompanyNumber  from #temp where rno != 1)

Answer 4

您可以在where语句中使用exists子句来查找带有重复项的空行：

delete
from   tableA
where  tableA.Status is null
and    exists (
           select *
           from   tableA t2
           where  t2.CompanyNumber = tableA.CompanyNumber 
           and    t2.Name = tableA.Name and not t2.Status is null
       )

如何在SQL中删除带条件的重复项

4 个答案: