Question

我有2个sql表

1。类别表

-id
-name
-url
-content

2.Entry表

-id
-title
-content
-cat //category
-view
-author

我想按条目表中的类别总数对所有类别进行排序

我想根据此查询返回的值对类别进行排序：

  SELECT count(cat) as catcount, 
         cat 
    FROM entry 
GROUP BY cat 
ORDER BY catcount DESC

此查询当前返回两个结果。我要打印的区域中有20个地方。我想将随机字段写入空白字段

  sample data: 
kitap
acil

expected data:
kitap
acil
random category.name 18 piece

Answer 1

您只想要一个left join吗？

SELECT c.id, COUNT(e.id) as catcount
FROM category c LEFT JOIN
     entry e
     ON c.id = e.cat
GROUP BY c.id 
ORDER BY catcount DESC ;

Answer 2

更理想的方法是将子查询分组，然后加入字典：

select c.cat_id, c.cat_name, e.cnt
from Categories as c
left join (
 select e.cat_id, count(*) as cnt
 from Entries as e
 group by e.cat_id
) as e
on e.cat_id = c.id
order by e.cnt desc

在另一个表格中按计数排序

2 个答案: