Json Array Column split into Rows SQL

Question

Currently I have in my DB(mariaDB 10.3) a column that is called data and contains a json array:

client| data
1     | '["a","b","c"]'
2     | '["k"]'

and I would like to brake it down into

client| data
1     | "a"
1     | "b"
1     | "c"
2     | "k"

Answer 1

Unfortunately, MariaDB does not support "unnesting" function JSON_TABLE(), unlike MySQL 8.0.

We are left with some kind of iterative approach, typicaly by using a table of numbers to enumerate the array elements. If you have a table with at least as many rows as the maximum number of elements in an array, say bigtable, you can do:

select client, json_unquote(json_extract(t.data, concat('$[', n.rn - 1, ']'))) value
from mytable t
inner join (select row_number() over() rn from bigtable) n
    on n.rn <= json_length(t.data)
order by t.client, n.rn

Demo on DB Fiddle:

client | value
-----: | :----
     1 | a    
     1 | b    
     1 | c    
     2 | k