Question

我有一个名为员工的表，此表中有许多记录。以下是一些示例数据：

fullname  | address  |  city
-----------------------------
AA          address1    City1
AA          address3    City1
AA          address8    City2
BB          address5    City2
BB          address2    City1
CC          address6    City1
CC          address7    City2
DD          address4    City1

我希望在sql server中有一个SELECT查询，它只显示基于列fullname和city的重复记录。对于给定的数据并考虑条件，只有前两个记录是重复的。所以我的预期输出应该如下：

fullname  | address  |  city
-----------------------------
AA          address1    City1
AA          address3    City1

要获得此输出，我已编写此查询：

select fullname, city from employee group by fullname, city having count(*)>1

如您所见，它仅选择两列，因此它提供以下输出：

fullname  | city
------------------
AA          City1

如果我重新编写如下查询：

select fullname, city, address from employee group by fullname, city, address 
having count(*)>1

不幸的是它显示没有记录！有人可以帮我写出正确的查询以获得预期的结果吗？

Answer 1

您可以将其用作窗口聚合来访问其他列，而不是分组COUNT

SELECT fullname,
       address,
       city
FROM   (SELECT *,
               COUNT(*) OVER (PARTITION BY fullname, city) AS cnt
        FROM   employee) e
WHERE  cnt > 1

Answer 2

同意上述答案。但是如果您不想使用可能无法在所有数据库上正常工作的Windows功能，您可以在城市和全名后加入自己的组，然后获取地址

   Select employee.* from employee 
   join (select fullname, city from employee group by fullname, city having count(*)>1) q1 
   on q1.fullname = employee.fullname and q1.city = employee.city

Answer 3

尝试以下代码：

      create table ##Employee
      (Fullname varchar(25),
       Address varchar(25),
       City varchar(25))

      insert into ##Employee values
     (    'AA',          'address1',    'City1')
    ,(    'AA',          'address3',    'City1')
    ,(    'AA',          'address8',    'City2')
    ,(    'BB',          'address5',    'City2')
    ,(    'BB',          'address2',    'City1')
    ,(    'CC',          'address6',    'City1')
    ,(    'CC',          'address7',    'City2')


      select E.* from ##Employee E
      cross apply(
      select Fullname,City,count(Fullname) cnt from ##Employee
      group by Fullname,City
      having Count(Fullname)>1)x
      where E.Fullname=x.Fullname
      and E.City=x.City

Answer 4

如果您有唯一的ID或地址总是不同，您可以尝试：

select e.*
from employee e
where exists (select 1
              from employee e2
              where e2.fullname = e.fullname and e2.city = e.city and
                    e2.address <> e.address  -- or id or some other unique column
             );

虽然我可能会使用窗口函数方法，但您可能会发现在某些情况下，这会更快（特别是如果您在employee(fullname, city, address)上有索引）。

Answer 5

您可以使用解决方案：

DECLARE  @Employee TABLE
        (
            Fullname VARCHAR(25),
            [Address] VARCHAR(25),
            City VARCHAR(25)
        )

      INSERT INTO @Employee VALUES
      ('AA', 'address1', 'City1') 
      ,('AA', 'address1', 'City1') 
      ,('AA', 'address3', 'City1')
      ,('AA', 'address8', 'City2')
      ,('BB', 'address5', 'City2')
      ,('BB', 'address2', 'City1')
      ,('CC', 'address6', 'City1')
      ,('CC', 'address7', 'City2')

     ;WITH cte AS (
               SELECT *,
                      ROW_NUMBER() OVER(PARTITION BY FullName, [Address], [City] ORDER BY Fullname) AS sl,
                      HashBytes('MD5', FullName + [Address] + [City]) AS RecordId
               FROM   @Employee AS e
           )

      SELECT c.FullName,
             c.[Address],
             c.City
      FROM   cte             AS c
             INNER JOIN cte  AS c1
                  ON  c.RecordId = c1.RecordId
      WHERE  c.sl = 2

结果：

FullName    Address     City
AA          address1    City1
AA          address1    City1

Answer 6

SELECT Feild1, Feild2, COUNT() FROM table name GROUP BY Feild1, Feild2 HAVING COUNT()>1

这会给你所有的答案

Sql查询只显示基于两列的重复记录

6 个答案: