[英]MySQL - Select all rows where a field value is not unique
How can I select all rows in MySQL where a particular field value is not unique. 如何在MySQL中选择特定字段值不唯一的所有行。 For example I have the following data:
例如,我有以下数据:
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| ID | Name | URL |
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| 1 | Store 1| http://www.store1.com |
| 2 | Store 2| http://www.store1.com |
| 3 | Store 3| http://www.store3.com |
| 4 | Store 4| http://www.store4.com |
| 5 | Store 5| http://www.store4.com |
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In this I would want to return the following where the URL field has duplicates: 在这里我想要返回URL字段有重复的以下内容:
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| ID | Name | URL |
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| 1 | Store 1| http://www.store1.com |
| 2 | Store 2| http://www.store1.com |
| 4 | Store 4| http://www.store4.com |
| 5 | Store 5| http://www.store4.com |
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or, old school... 或者,老派......
SELECT DISTINCT x.*
FROM my_table x
JOIN my_table y
ON y.url = x.url
AND y.id <> x.id
ORDER
BY id;
If you want all the original rows, then use exists
: 如果您想要所有原始行,则使用
exists
:
select t.*
from table t
where exists (select 1 from table t2 where t2.url = t.url and t2.id <> t.id);
You can inner join to your duplicates. 您可以内部联接到您的副本。
select t.*
from table t
inner join
(select url from table group by 1 having count(*)>1) duplicates
on duplicates.url=t.url
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