按字母顺序对varchar2中的字符进行排序 [英] Sort chars in varchar2 alphabetically

问题描述

我正在寻找一个函数，该函数可以按字母顺序对varchar2中的char进行排序.

I'm looking for a function that would sort chars in varchar2 alphabetically.

是否可以在oracle中内置某些东西，或者需要在PL/SQL中创建自定义?

Is there something built-in into oracle that I can use or I need to create custom in PL/SQL ?

推荐答案

来自 http://forums.oracle.com/forums/thread.jspa?messageID=1791550 这可能有效，但没有10g的测试...

From an answer at http://forums.oracle.com/forums/thread.jspa?messageID=1791550 this might work, but don't have 10g to test on...

SELECT MIN(permutations)
FROM (SELECT REPLACE (SYS_CONNECT_BY_PATH (n, ','), ',') permutations
    FROM (SELECT LEVEL l, SUBSTR ('&col', LEVEL, 1) n
        FROM DUAL
        CONNECT BY LEVEL <= LENGTH ('&col')) yourtable
    CONNECT BY NOCYCLE l != PRIOR l)
WHERE LENGTH (permutations) = LENGTH ('&col')

在示例中，col是在SQL * Plus中定义的，但是如果您将此功能设为函数，则可以传递它，或者可以重新构造它以直接获取表列.

In the example col is defined in SQL*Plus, but if you make this a function you can pass it in, or could rework it to take a table column directly I suppose.

我将其作为起点而不是解决方案；最初的问题是关于字谜的，所以它旨在查找所有排列，因此可能会进行相似但简化的操作.我怀疑这对于较大的值来说缩放效果不是很好.

I'd take that as a start point rather than a solution; the original question was about anagrams so it's designed to find all permutations, so something similar but simplified might be possible. I suspect this doesn't scale very well for large values.

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