如何select所有分类并统计MySQL中每个分类文章的数量

Question

类别table：

id, name
---------
1   cat1
2   cat2
3   cat3 
4   cat4

文章table：

id, cid, title
--------------
1   1    title1
2   3    title2
3   1    title3
4   2    title4

如何select所有分类并统计MySQL中每个分类的文章数？我需要一个 mysql 查询，它将 select 所有类别和属于每个类别的文章总数并按类别 ID 排序。

预期输出table：

+-------+-------+    
|  name | count |    
+-------+-------+    
|  cat1 |     2 |    
|  cat2 |     1 |    
|  cat3 |     1 |  
|  cat4 |     0 |  
+-------+-------+

Answer 1

试试这个：

SELECT c.`name`, count(a.cid) as count FROM category
LEFT JOIN article
ON c.id = a.cid
GROUP BY a.cid

Answer 2

select c.name,count(b.title)count from category a, article b where c.id = a.cid group by c.name order by a.cid;

Answer 3

SELECT
    c.`name`,
    COUNT(a.cid) AS `count`
FROM
    categories c
    LEFT JOIN article a ON c.id = a.cid
GROUP BY
    c.`name`
ORDER BY
    c.`name`

Answer 4

我希望这会奏效。请检查。

select
    Category.name.
    ifnull(count(Article.cid),0) as count
FROM
    Category
LEFT JOIN
    Article 
on
    Article.cid=Category.id
group by
    Category.Id

Answer 5

你也可以使用像

这样的子查询

SELECT c.name,(select count(*) from article where cid = c.id) as count  FROM cat c WHERE 1 GROUP BY c.id

如何select所有分类并统计MySQL中每个分类文章的数量

How to select all categories and count number of each category articles in MySQL

php

mysql

categories