2
在查询中使用它之前,可以对值列表进行排序吗?MySQL:在查询中使用它之前对值进行排序
赞SELECT SORTINGFN(2,3,1)
并得到1,2,3
? 类似SELECT 2,3,1 ORDER BY ??? ASC
,但按顺序排序?
我需要确保的参数总是以相同的顺序,从MD5('1,2,3')
和MD5('2,3,1')
在查询中使用它之前,可以对值列表进行排序吗?MySQL:在查询中使用它之前对值进行排序
赞SELECT SORTINGFN(2,3,1)
并得到1,2,3
? 类似SELECT 2,3,1 ORDER BY ??? ASC
,但按顺序排序?
我需要确保的参数总是以相同的顺序,从MD5('1,2,3')
和MD5('2,3,1')
得到相同的哈希没有表(设定值argx
):
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
输出:
╔════╦════╦════╦══════════════════════════════════╗
║ 1 ║ 2 ║ 3 ║ md5_checksum ║
╠════╬════╬════╬══════════════════════════════════╣
║ 1 ║ 2 ║ 3 ║ 55b84a9d317184fe61224bfb4a060fb0 ║
║ 3 ║ 2 ║ 1 ║ 55b84a9d317184fe61224bfb4a060fb0 ║
║ 3 ║ 1 ║ 2 ║ 55b84a9d317184fe61224bfb4a060fb0 ║
╚════╩════╩════╩══════════════════════════════════╝
无论如何MD5
是弱散列算法。
SQL可以做很多事情。问题是这样的操作的好地方,当你可以在应用层做到这一点。
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
输出:
╔══════════════════════╦══════════════════════════════════╗
║ args ║ md5_sum ║
╠══════════════════════╬══════════════════════════════════╣
║ 3,2,1,10,212,3123,1 ║ e2003296ed64cb59be61558275e22433 ║
║ 212,3123,1,3,2,1,10 ║ e2003296ed64cb59be61558275e22433 ║
╚══════════════════════╩══════════════════════════════════╝
我需要的ID从应用程序来与MySQL进行排序。没有包含该ID的表格,它们只是参数。 是的,我可以在应用程序中对它们进行排序,但也许可以用MySQL,只是为了好奇。 –
有趣的想法,但ID列表具有任意长度 –
@Kanstantsin问题在哪里?只需添加更多参数'(SELECT arg1 AS col UNION ALL SELECT arg2 UNION ALL SELECT arg3 UNION ALL ...)' – lad2025