Question

我需要一个mysql SELECT，它选择最后20个ID，它显示7点击率最高，但是从最后20个点开始，7个点击次数最多......而不是来自我尝试过DESC和LIMIT的所有ID但不是working..any idea ??

SELECT * FROM search ORDER BY clicks DESC, id DESC LIMIT 20

或

SELECT * FROM search ORDER BY id DESC LIMIT 20
SELECT * FROM search ORDER BY clicks DESC LIMIT 7

或者

SELECT * FROM search ORDER BY id DESC LIMIT 20 UNION SELECT * FROM search ORDER BY clicks DESC LIMIT 7

Answer 1

试试这个

SELECT * FROM 
(
    SELECT * FROM search ORDER BY id DESC LIMIT 20
) SUB
ORDER BY clicks DESC LIMIT 7

修改

SUB在做什么..？

SUB 是子查询SELECT * FROM search ORDER BY id DESC LIMIT 20的别名。它可能有不同的名称，由你决定。

SELECT * FROM /*<=== Query 2 - Will be executed after Query 1 is run, thus will perform a search within the results returned by Query1*/ ( SELECT * FROM search ORDER BY id DESC LIMIT 20 /*<=== SUBQUERY - Query 1 - Will be executed first */ ) ORDER BY clicks DESC LIMIT 7

我们要去的是那个;首先，我们使用search SUB 从SELECT * FROM search ORDER BY id DESC LIMIT 20获取最近20行的结果集，然后我们运行SELECT查询 IN SUB 返回的结果集。

Answer 2

试试这个：

您的查询应该是

SELECT * FROM search ORDER BY clicks DESC LIMIT 0, 20

或

SELECT * FROM search ORDER BY id DESC LIMIT 0, 20

其中“0”代表结果的起始位置，“20”代表结果的长度。

带有双重限制的双DESC

2 个答案: