Question

我正在尝试

select columns Age, Height, House_number, Street
from my_table
where count(combination of House_number, Street)
occurs more than once.

我的表格看起来像这样

Age, Height, House_number, Street
15   178     6             Mc Gill Crst 
85   166     6             Mc Gill Crst
85   166     195           Mc Gill Crst
18   151     99            Moon Street 
52   189     14a           Grimm Lane

我希望的结果看起来像这样

Age, Height, House_number, Street
15   178     6             Mc Gill Crst 
85   166     6             Mc Gill Crst

粘住！

Answer 1

最好的方法是使用窗口函数，假设您的数据库支持它们：

select columns Age, Height, House_number, Street
from (select t.*, count(*) over (partition by house_number, street) as cnt
      from my_table t
     ) t
where cnt > 1

这是在Oracle中使用Windows功能（也称为分析功能）。表达式count(*) over (partition by house_number, street)计算每个house_number和街道组合的行数。这有点像做group by，但它会将计数添加到每一行，而不是将多行合并为一行。

完成后，只需选择值大于1的行即可。

Answer 2

由于您没有提到您正在使用的RDBMS，因此下面的查询将在大多数RDBMS上工作。

SELECT  *
FROM    tableName
WHERE   (House_number, Street) IN
(
    SELECT House_number, STREET
    FROM tableName
    GROUP BY House_number, STREET
    HAVING COUNT(*) >= 2
)

SQLFiddle Demo

Answer 3

听起来你需要一个NOT DISTINCT。以下内容可能会为您提供所需内容：Multiple NOT distinct

Answer 4

如果您没有窗口函数，则可以使用带有JOIN的子查询。子查询获取计数大于1的house_number和street列表，然后将此结果用于连接回您的表：

select t1.age,
  t1.height,
  t1.house_number,
  t1.street
from my_table t1
inner join
(
  select house_number, street
  from my_table 
  group by house_number, street
  having count(*) > 1
) t2
  on t1.house_number = t2.house_number
  and t1.street = t2.street

请参阅SQL Fiddle with Demo

SQL查找只有2列值的整行

4 个答案: