user表结构如下图所示:
现在要分割user表中id=41的数据,分割的列为address,按照","分割,把分割后的每一条数据转化为列,sql语句:
SELECT
a.id,a.`username`,SUBSTRING_INDEX(SUBSTRING_INDEX(a.`address`, ',', b.help_topic_id + 1 ), ',', -1) AS address
FROM
`user` AS a
JOIN mysql.help_topic AS b ON b.help_topic_id < (LENGTH(a.`address`) - LENGTH(REPLACE(a.`address`, ',', '')) + 1 )
WHERE a.`id` = 41;
查询结果如下图所示: