MySQL查詢限制類別數

Question

我有一個查詢按類別顯示帖子。我只需要顯示前5個類別的結果。我的查詢顯示類別和類別的數量。該查詢顯示每個類別中的所有類別和帖子數量。

我想限制類別的顯示。

我有這個疑問：

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

這是表結構，我有

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

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

Answer 1

您需要在您的查詢

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

我想你需要什麼是極限：

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

限制應有所幫助。

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然後使用TOP如果MySQL或PostgreSQL然後使用LIMIT。