具有分组依据和行数的SQL

Question

我有一张桌子：

ID | domain       | address
=======================================
 1 | example.com  | example.com/siteA
 2 | example.com  | example.com/siteB
 3 | example.com  | sub.example.com
 4 | example.com  | sub.example.com/dir
 5 | foobar.com   | foobar.com/site123
 6 | foobar.com   | foobar.com/site
 ...

现在我想知道一个域有多少“地址”

ID | domain       | count
==========================
 1 | example.com  | 4
 5 | foobar.com   | 4

我的陈述目前是

SELECT * FROM table GROUP BY domain

我知道这只是一张桌子，或者我应该把它分成两张？

Answer 1

SELECT domain, COUNT(domain) as Count FROM table GROUP BY domain

更新：获取ID

SELECT MIN(ID) ID, domain, COUNT(domain) as Count FROM table GROUP BY domain

OR，另一种方式：

SELECT 
 (SELECT MIN (ID) FROM table WHERE DOMAIN = A.DOMAN) AS ID
domain, 
COUNT(domain) as Count 
FROM table A GROUP BY domain

Answer 2

<强> Read Group by

select min(ID) as ID,domain,count(1) as Count
from table 
group by domain

Answer 3

您正在寻找此输出：

ID | domain       | count
==========================
 1 | example.com  | 4
 5 | foobar.com   | 4

这是查询（假设每个域的每个地址都是唯一的）：

SELECT MAX(ID), domain, COUNT(*) as count FROM table GROUP BY domain