MySql 查询记录

1.分割字符串返回表对象

SELECT SUBSTRING_INDEX(SUBSTRING_INDEX('0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23',',',help_topic_id+1),',',-1) AS num 
FROM mysql.help_topic 
WHERE help_topic_id < LENGTH('0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23')-LENGTH(REPLACE('0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23',',',''))+1

 2.