mysql - MySql：如何将 rownumber 与 join Query 语句一起使用？

Question

我有一个 MySQL 语句，它连接 2 个表并以字段“touch”的 Desc 顺序显示结果。这是我的 SQL 语句

SELECT @rownum := @rownum +1 rownum, 
(IF( dm.Brand_FULL = '1', dd.Device_Brand, dm.Brand_Full )) AS Brand,
dd.Device_Model AS Model, 
CONCAT( dm.Service_provider, ' ', dm.Model_Full ) AS 'Marketing Name', 
max( Touch_Count ) AS Touch FROM Device_Details dd 
JOIN Device_Models dm ON dd.Device_Model = dm.Model_Short, 
(SELECT @rownum :=0 )r GROUP BY dd.Device_Model ORDER BY Touch_Count DESC

这给了我这样的结果

结果是完美的，它基于Touch字段的降序。现在的问题是rownum没有按顺序排列。那么如何修改 mySQL 语句，以便我可以在不更改 Touch 字段的 DESC 顺序的情况下按顺序获取 rownum。

Answer 1

使用子查询：

SELECT
    @rownum := @rownum + 1 AS rownum,
    T1.*
FROM
(
    SELECT
        IF(dm.Brand_Full = '1', dd.Device_Brand, dm.Brand_Full) AS Brand,
        dd.Device_Model AS Model, 
        CONCAT(dm.Service_provider, ' ', dm.Model_Full) AS 'Marketing Name', 
        MAX(Touch_Count) AS Touch
    FROM Device_Details dd 
    JOIN Device_Models dm
    ON dd.Device_Model = dm.Model_Short
    GROUP BY dd.Device_Model
) AS T1, (SELECT @rownum := 0) AS r
ORDER BY Touch DESC