mysql列转行 行转列

            SELECT
             
     flag
    ,substring_index(substring_index(t.context,
            ‘
            ,
            ‘, b.help_topic_id +1), ‘,‘, -1) as result
FROM (
    select‘aa‘as flag,‘1,2,3,4,5,6,7‘as context unionallselect‘bb‘as flag,‘1,2,3,4,5,6‘as context unionallselect‘cc‘as flag,‘1,2,3,4,5‘as context unionallselect‘dd‘as flag,‘1,2,3,4‘as context unionallselect‘ee‘as flag,‘1,2,3‘as context 
) t 
join (
    select0as help_topic_id unionallselect1as help_topic_id unionallselect2as help_topic_id unionallselect3as help_topic_id unionallselect4as help_topic_id unionallselect5as help_topic_id unionallselect6as help_topic_id unionallselect7as help_topic_id unionallselect8as help_topic_id unionallselect9as help_topic_id
) b 
    ON b.help_topic_id < (LENGTH(t.context) - LENGTH(REPLACE(t.context, ‘,‘, ‘‘)) +1)
orderby flag,result
;

            select
            
     name
    ,group_concat(age) 
            as
             ages

            from
             (
    
            select
            ‘
            a
            ‘
            as name, 0as age unionallselect‘b‘as name, 1as age unionallselect‘b‘as name, 2as age unionallselect‘c‘as name, 3as age unionallselect‘c‘as name, 4as age unionallselect‘c‘as name, 5as age unionallselect‘d‘as name, 6as age unionallselect‘d‘as name, 7as age unionallselect‘d‘as name, 8as age unionallselect‘d‘as name, 9as age
) b 
groupby name
;