使用行排序的SQL子查詢的顛倒順序

Question

我有一個MySQL表，它包含有關程序功能使用情況的統計信息。我從中檢索基本上就像這樣（前15名總點擊這裏）：

SELECT function_id, data_timer, SUM(data_counter) total 
FROM data 
GROUP BY function_id 
ORDER BY total DESC 

+-------------+------------+-------+ 
| function_id | data_timer | total | 
+-------------+------------+-------+ 
|   56 |  567 | 4389 | 
|   23 |  7880 | 1267 | 
|   7 |  145 | 812 | 
|   ... |  ... | ... | 
+-------------+------------+-------+ 

由於這些結果網站模塊中，用戶可以選擇哪些列將用於ORDER BY以及ASC之間和DESC，我需要檢索排名的每行結果。

有了這個question的幫助下，我才得以將排序分配的結果的每一行：

SET @rank = 0; 
SELECT @rank:=@rank+1 AS rank, function_id, data_timer, SUM(data_counter) total 
FROM data 
WHERE client_id = 2 
GROUP BY function_id 
ORDER BY total DESC 

+------+-------------+------------+-------+ 
| rank | function_id | data_timer | total | 
+------+-------------+------------+-------+ 
| 1 |   56 |  567 | 4389 | 
| 2 |   23 |  7880 | 1267 | 
| 3 |   7 |  145 | 812 | 
| ... |   ... |  ... | ... | 
+------+-------------+------------+-------+ 

我現在有一些困難，試圖顛倒這個表，這意味着我想有結果首先用最少使用的函數排序。像這樣的東西（假設有76起）：

+------+-------------+------------+-------+ 
| rank | function_id | data_timer | total | 
+------+-------------+------------+-------+ 
| 76 |   44 |  346 |  1 | 
| 75 |   2 |  3980 |  4 | 
| 74 |   13 |  612 |  7 | 
| ... |   ... |  ... | ... | 
+------+-------------+------------+-------+ 

這裏是我的SQL查詢的嘗試：

SELECT rank, function_id, data_timer, total 
FROM 
(
SET @rank = 0; 
SELECT @rank:=@rank+1 AS rank, function_id, data_timer, SUM(data_counter) total 
FROM data 
WHERE client_id = 2 
GROUP BY function_id 
ORDER BY total DESC 
) 
ORDER BY rank DESC 

它不斷出現我：

#1064 - You have an error in your SQL syntax; check the manual that 
corresponds to your MySQL server version for the right syntax to use near 
'SET @rank = 0' at line 4 

因爲我不是對SQL太熟練了，我猜我錯過了一些明顯的東西。

任何幫助將不勝感激，謝謝！

Answer 1

您正試圖在您的子查詢中分配一個變量。這不起作用。將分配移動到子查詢之外，它應該運行。

SET @rank = 0; 
SELECT rank, function_id, data_timer, total 
FROM 
(
SELECT @rank:=@rank+1 AS rank, function_id, data_timer, SUM(data_counter) total 
FROM data 
WHERE client_id = 2 
GROUP BY function_id 
ORDER BY total DESC 
) 
ORDER BY rank DESC 

Answer 2

另一種選擇是在查詢初始化你@rank變量，而不是一個單獨的語句：

SELECT rank, function_id, data_timer, total 
FROM 
(
    SELECT @rank:=@rank+1 AS rank, function_id, data_timer, SUM(data_counter) total 
    FROM data, 
     (SELECT @rank := 0) r 
    WHERE client_id = 2 
    GROUP BY function_id 
    ORDER BY total DESC 
) r 
ORDER BY rank DESC 

• Condensed SQL Fiddle Demo