MySQL查询限制类别数

Question

我有一个查询按类别显示帖子。我只需要显示前5个类别的结果。我的查询显示类别和类别的数量。该查询显示每个类别中的所有类别和帖子数量。

我想限制类别的显示。

我有这个疑问：

SELECT qp_category, name, count(qp_category) as Total 
FROM questionpapers 
INNER JOIN 
questioncategory 
ON 
questionpapers.qp_category = questioncategory.qcid 
GROUP BY qp_category; 

这是表结构，我有

category table 
-------------------------- 
qcid | name | active 
-------------------------- 

post table 
-------------------------------------------------------- 
qpid | title | qp_category | description | date | active 
-------------------------------------------------------- 

Answer 1

您需要在您的查询

SELECT qp_category, name, count(qp_category) as Total 
FROM questionpapers 
INNER JOIN questioncategory ON questionpapers.qp_category = questioncategory.qcid 
GROUP BY qp_category LIMIT 5; 

Answer 2

我想你需要什么是极限：

SELECT qp_category, name, count(qp_category) as Total 
FROM questionpapers 
INNER JOIN 
questioncategory 
ON 
questionpapers.qp_category = questioncategory.qcid 
GROUP BY qp_category 
LIMIT 5; 

Answer 3

限制应有所帮助。

SELECT qp_category, name, count(qp_category) as Total 
FROM questionpapers 
INNER JOIN questioncategory ON questionpapers.qp_category = questioncategory.qcid 
GROUP BY qp_category 
LIMIT 5; 

FYI：如果SQL Server然后使用TOP如果MySQL或PostgreSQL然后使用LIMIT。