select 

substring_index(

    substring_index(

      t.com,

      '@',

      b.help_topic_id + 1

    ),

    '@' ,- 1

  ) AS com_row,

b.help_topic_id,

t.com,

 substring_index(

      t.com,

      '@',

      b.help_topic_id + 1

    ) as new_com

 from (

select 'f005@13466664685@f0006@3667477@f0008@3555' as com

) t 

JOIN mysql.help_topic b ON b.help_topic_id < (

  length(t.com) - length(

    REPLACE (t.com, '@', '')) + 1)

自己改一下就行了

有个笨方法用union all 连接  不晓得是不是你要的

SELECT COLNUM1,NULL AS 'COLNUM2' ,NULL AS 'COLNUM3',NULL 'COLNUM4' FROM TABLE 

UNION ALL

SELECT COLNUM1,COLNUM2 ,NULL AS 'COLNUM3',NULL 'COLNUM4' FROM TABLE

UNION ALL

UNION ALL

SELECT COLNUM1,COLNUM2 ,COLNUM3,NULL 'COLNUM4' FROM TABLE

UNION ALL

SELECT COLNUM1,COLNUM2 ,COLNUM3,COLNUM4 FROM TABLE