我有一个 MySQL 表,其中包含有关程序函数使用情况的统计信息。我从中检索到的内容基本上是这样的(这里总共前 15 名):
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 |
| ... | ... | ... |
+-------------+------------+-------+
由于这些结果用于网站模块,用户可以在其中选择将用于 ORDER BY 的列以及 ASC 和 DESC 之间的列,因此我需要检索结果每行的排名。
在这个问题的帮助下,我能够为结果的每一行分配一个等级:
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 |
| ... | ... | ... | ... |
+------+-------------+------------+-------+
我现在在尝试反转此表时遇到了一些困难,这意味着我希望首先使用最少使用的函数对结果进行排序。像这样(假设有 76 个函数):
+------+-------------+------------+-------+
| rank | function_id | data_timer | total |
+------+-------------+------------+-------+
| 76 | 44 | 346 | 1 |
| 75 | 2 | 3980 | 4 |
| 74 | 13 | 612 | 7 |
| ... | ... | ... | ... |
+------+-------------+------------+-------+
这是我的 SQL 查询尝试:
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
它一直在弹出我这个:
#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
由于我对 SQL 不太熟练,我想我遗漏了一些明显的东西。
任何帮助将不胜感激,谢谢!