問(wèn)題描述

源表:

字典表:

期望將源表的數(shù)值根據(jù)字典表進(jìn)行替換,目標(biāo)結(jié)果如下:

嘗試過(guò)用replace函數(shù),但是只能單個(gè)替換.(注:其他由于是逗號(hào)分隔,字典表id可1~100,需要用正則表達(dá)式替換,否則12會(huì)被id1,2拆開(kāi))

問(wèn)題解答

自己寫(xiě)的遞歸函數(shù)

DELIMITER $$DROP FUNCTION IF EXISTS junk.StringReplaceSplit $$CREATE FUNCTION junk.StringReplaceSplit (v_str VARCHAR(1024), v_split VARCHAR(1024)) RETURNS VARCHAR(1024)DETERMINISTICBEGIN??DECLARE rv VARCHAR(1024);??DECLARE splist_count INT;??DECLARE i INT;??DROP TEMPORARY TABLE IF EXISTS tmp_table;??CREATE TEMPORARY TABLE tmp_table(v_key VARCHAR(100));???SET i = 1;??set splist_count = (length(v_str)-length(replace(v_str, v_split,’’)))/length(v_split)+1;??WHILE i <= splist_count DO????INSERT INTO tmp_table??????SELECT REPLACE(substring(substring_index(v_str, v_split, i),?????????????????????length(substring_index(v_str, v_split, i-1)) + 1),??????????????????????v_split, ’’);????SET i = i + 1;??END WHILE;??SELECT replace(group_concat(ifnull(wordlist.word, tmp_table.v_key)), ’,’, v_split) INTO rv????from tmp_table????LEFT JOIN wordlist on wordlist.id=tmp_table.v_key;??RETURN rv;END $$DELIMITER ;

效果:源表

mysql> select * from teststring;+----+----------------------------+| id | String |+----+----------------------------+| 1 | 1,2,3,4,5 || 2 | 4,5,7,8,84 || 3 | key,23,344,12,3,9,34,3,1,3 |+----+----------------------------+3 rows in set (0.00 sec)

字典表

mysql> select * from wordlist;+----+-------+| id | word |+----+-------+| 1 | one || 2 | two || 3 | three || 4 | four || 5 | five || 7 | six || 8 | eight || 9 | nine || 10 | ten |+----+-------+9 rows in set (0.00 sec)

示例:

mysql> SELECT id, StringReplaceSplit(String,’,’) transform from teststring ;+----+---------------------------------------------+| id | transform |+----+---------------------------------------------+| 1 | one,two,three,four,five || 2 | four,five,six,eight,84 || 3 | key,23,344,12,three,nine,34,three,one,three |+----+---------------------------------------------+3 rows in set (0.04 sec)

函數(shù)有待優(yōu)化.