sqlite - 我想要只有字符(完全没有符号、数字和空格)

Question

应该用 SQLite 完成

像这样;



是的，我知道，这很容易，如果我使用 UDF (用户定义函数)。

但是，我对此有很大的困难。

所以，寻找另一种方式( 没有 UDF 方式)来实现我的目标。

谢谢

供您引用，

我留下了一个我未能制作 UDF 的链接(使用 AutoHotkey)

SQLite/AutoHotkey, I have problem with Encoding of sqlite3_result_text return function

Answer 1

我相信您可以将决议基于:-

WITH RECURSIVE eachchar(counter,rowid,c,rest) AS (
        SELECT 1,rowid,'',mycolumn AS rest FROM mytable
        UNION ALL 
            SELECT counter+1,rowid,substr(rest,1,1),substr(rest,2) FROM eachchar WHERE length(rest) > 0 LIMIT 100
    )
SELECT group_concat(c,'') AS mycolumn, myothercolumn, mycolumn AS original
FROM eachchar JOIN mytable ON eachchar.rowid = mytable.rowid 
WHERE length(c) > 0 
    AND (
        unicode(c) BETWEEN unicode('a') AND unicode('z') 
        OR unicode(c) BETWEEN unicode('A') AND unicode('Z')
    )
GROUP BY rowid;

演示:-

也许考虑以下几点:-

/* Create the Test Environment */
DROP TABLE IF EXISTS mytable;
CREATE TABLE IF NOT EXISTS mytable (mycolumn TEXT, myothercolumn);
/* Add the Testing data */
INSERT INTO mytable VALUES
    ('123-abc_"D E F()[]{}~`!@#$%^&*-+=|\?><<:;''','A')
    ,('123-xyz_"X Y Z()[]{}~`!@#$%^&*-+=|\?><<:;''','B')
    ,('123-abc_"A B C()[]{}~`!@#$%^&*-+=|\?><<:;''','C')
;

/* split each character thenconcatenat only the required characters*/
WITH RECURSIVE eachchar(counter,rowid,c,rest) AS (
        SELECT 1,rowid,'',mycolumn AS rest FROM mytable
        UNION ALL 
            SELECT counter+1,rowid,substr(rest,1,1),substr(rest,2) FROM eachchar WHERE length(rest) > 0 LIMIT 100
    )
SELECT group_concat(c,'') AS mycolumn, myothercolumn, mycolumn AS original
FROM eachchar JOIN mytable ON eachchar.rowid = mytable.rowid 
WHERE length(c) > 0 
    AND (
        unicode(c) BETWEEN unicode('a') AND unicode('z') 
        OR unicode(c) BETWEEN unicode('A') AND unicode('Z')
    )
GROUP BY rowid;
/* Cleanup Test Environment */
DROP TABLE IF EXISTS mytable;

这导致: -