MySQL的计数复制

Question

我有这样

mysql> desc user_changes; 
+----------+--------------+------+-----+---------+-------+ 
| Field | Type   | Null | Key | Default | Extra | 
+----------+--------------+------+-----+---------+-------+ 
| id  | varchar(16) | NO | PRI |   |  | 
| email | varchar(255) | YES | MUL | NULL |  | 
| products | longtext  | YES |  | NULL |  | 
+----------+--------------+------+-----+---------+-------+ 
3 rows in set (0.00 sec) 

一个表，我需要创建一个查询，将通过电子邮件算上所有重复这样

| 20061129180346 | test@test.com | 1^31^9 
| 20061129330638 | test@test.com | 1^31^9 

Answer 1

SELECT count(*), email 
FROM  user_changes 
GROUP BY email 
HAVING count(*) > 1 

最后（HAVING ）子句将选择限制为大于1的电子邮件计数，例如重复。

Answer 2

select 
    email, 
    count(email) as email_count 
from 
    user_changes 
group by 
    email 
having 
    count(email) > 1 
order by 
    email asc 

Answer 3

我不明白你的第二块，但要获得每封电子邮件的数量做

SELECT email, COUNT(*) AS count FROM user_changes GROUP BY email WHERE count > 1; 

Answer 4

select email, count(*) 
from user_changes 
group by email 
having count(*) > 1 

Answer 5

这算多少每个电子邮件地址没有在表中，不考虑电子邮件地址的情况。例如，“test@test.com”和“TEST@TEST.COM”将被视为相同的电子邮件地址。它也只显示重复项，任何刚刚发生的电子邮件地址都不会被退回。如果你想要返回这些，只需省略“HAVING”子句。

SELECT LOWER(email) EmailAddress, COUNT(*) EmailCount 
    FROM user_changes 
GROUP BY LOWER(email) 
HAVING COUNT(*) > 1;