Question

我可以在查询中使用它之前对值列表进行排序吗？

赞SELECT SORTINGFN(2,3,1)并获得1,2,3？像SELECT 2,3,1 ORDER BY ??? ASC这样的东西，但按什么排序？

我需要确保参数始终采用相同的顺序，以便从MD5('1,2,3')和MD5('2,3,1')

获取相同的哈希值

Answer 1

没有表格（argx的设定值）：

SELECT arg1,arg2,arg3,
   MD5(SELECT GROUP_CONCAT(col ORDER BY col) 
       FROM (SELECT arg1 AS col
             UNION ALL SELECT arg2 
             UNION ALL SELECT arg3) AS sub) AS md5_checksum

的 SqlFiddleDemo

输出：

╔════╦════╦════╦══════════════════════════════════╗ ║ 1 ║ 2 ║ 3 ║ md5_checksum ║ ╠════╬════╬════╬══════════════════════════════════╣ ║ 1 ║ 2 ║ 3 ║ 55b84a9d317184fe61224bfb4a060fb0 ║ ║ 3 ║ 2 ║ 1 ║ 55b84a9d317184fe61224bfb4a060fb0 ║ ║ 3 ║ 1 ║ 2 ║ 55b84a9d317184fe61224bfb4a060fb0 ║ ╚════╩════╩════╩══════════════════════════════════╝

无论如何MD5是弱哈希算法。

SQL可以做很多事情。问题是这种操作的好地方，当你可以在应用层进行时。

任意列表：

SELECT MD5(GROUP_CONCAT(val ORDER BY val)) AS md5_sum FROM ( SELECT SUBSTRING_INDEX(SUBSTRING_INDEX(t.results, ',', n.n), ',', -1) AS val FROM (SELECT '3,2,1,10,212,3123,1' AS results) AS t CROSS JOIN ( SELECT a.N + b.N * 10 + 1 n FROM (SELECT 0 AS N UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9) a ,(SELECT 0 AS N UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9) b ) n WHERE n.n <= 1 + (LENGTH(t.results) - LENGTH(REPLACE(t.results, ',', ''))) ) sub

的 SqlFiddleDemo2

输出：

╔══════════════════════╦══════════════════════════════════╗ ║ args ║ md5_sum ║ ╠══════════════════════╬══════════════════════════════════╣ ║ 3,2,1,10,212,3123,1 ║ e2003296ed64cb59be61558275e22433 ║ ║ 212,3123,1,3,2,1,10 ║ e2003296ed64cb59be61558275e22433 ║ ╚══════════════════════╩══════════════════════════════════╝

MySQL：在查询中使用它之前对值列表进行排序

1 个答案: