SQL 查询、计数和分组依据
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时间：2020-08-31 23:04:43 来源:igfitidea点击:
SQL query, count and group by
提问by Dan
If I have data like this:
如果我有这样的数据：
+---+----+
|Key|Name|
+---+----+
|1 |Dan |
+---+----+
|2 |Tom |
+---+----+
|3 |Jon |
+---+----+
|4 |Tom |
+---+----+
|5 |Sam |
+---+----+
|6 |Dan |
+---+----+
What is the SQL query to bring back the records where Nameis repeated 2 or more times?
带回Name重复 2 次或更多次记录的 SQL 查询是什么？
So the result I would want is
所以我想要的结果是
+---+
|Tom|
+---+
|Dan|
+---+
回答by GateKiller
Couldn't be simpler...
不能更简单...
Select Name, Count(Name) As Count
From Table
Group By Name
Having Count(Name) > 1
Order By Count(Name) Desc
This could also be extended to delete duplicates:
这也可以扩展为删除重复项：
Delete From Table
Where Key In (
Select Max(Key)
From Table
Group By Name
Having Count(Name) > 1
)
回答by Ryan
select name from table group by name having count(name) > 1
回答by Dag Haavi Finstad
This could also be accomplished by joining the table with itself,
这也可以通过将表与自身连接来实现，
SELECT DISTINCT t1.name
FROM tbl t1
INNER JOIN tbl t2
ON t1.name = t2.name
WHERE t1.key != t2.key;
