mysql - 如何将一列中的多个值与其他列合并，该列也有多个由逗号分隔的值

Question

column1 | column2 | Result
32,33   | A,B     | A32,A33,B32,B33

我在上面给出了一个示例，其中我有两列，其中有多个值，用逗号分隔，我想合并前两列并希望获得结果列中所示的结果。

Answer 1

在 MySQL 8.0 上，您可以首先根据逗号分隔值拆分列 -

 with recursive col1 as (select 1 id, '32,33' as column1
                         union all
                         select 2, '34,35'),
      rec_col1 as (select id, column1 as remain, substring_index( column1, ',', 1 ) as column1
                   from col1
                   union all
                   select id, substring( remain, char_length( column1 )+2 ),substring_index( substring( remain, char_length( column1 ) +2  ), ',', 1 )
                   from rec_col1
                   where char_length( remain ) > char_length( column1 )

结果

id  column1
1   32
1   33
2   34
2   35

同样，第二列 -

with recursive col2 as (select 1 id, 'A,B' as column2
                        union all
                        select 2, 'C,D'),
     rec_col2 as (select id, column2 as remain, substring_index( column2, ',', 1 ) as column2
                  from col2
                  union all
                  select id, substring( remain, char_length( column2 )+2 ),substring_index( substring( remain, char_length( column2 ) +2  ), ',', 1 )
                  from rec_col2
                  where char_length( remain ) > char_length( column2 ))
select id, column2 from rec_col2
order by id;

结果

id  column2
1   A
1   B
2   C
2   D

拆分两列后，您可以根据 id 连接它们 -

select concat(c2.column2, c1.column1) result_rows
from rec_col1 c1
join rec_col2 c2 on c1.id = c2.id

结果

result_rows
A32
B32
C34
D34
A33
B33
C35
D35

最后你可以使用 GROUP_CONCAT 来组合它们 -

select group_concat(c2.column2, c1.column1 order by c2.column2, c1.column1) result
from rec_col1 c1
join rec_col2 c2 on c1.id = c2.id 
group by c2.id

<强> RESULT

result
A32,A33,B32,B33
C34,C35,D34,D35