记录/行计数等于2的条目总数

Question

我有一个条目表：id，name

用户可以根据需要输入多次。

我想检索已输入2次的用户总数。

所以如果表格如下：

user_id   name
-------   ----
3         chuck
4         larry
5         george
3         chuck
4         larry

查询将返回2，因为user_id 3和4是唯一在条目表中有两个条目的用户。

Answer 1

使用count(*)方法

select userid,count(*) as count 
from (select count(*) as c,userid 
      from entries 
      here c>=2 group by user_id) 
as dummy_table

Answer 2

试试这个：

SELECT count(*)
FROM
(
SELECT count(*) as count
FROM table_name
GROUP BY name
HAVING count = 2
)

Answer 3

试试这个：

select user_id , count(name) as c from table_name GROUP BY user_id having count(*) = 2

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