红移 SQL - 反向列表 function

Question

Suppose I have a table like below:

Name   Order
 AA     1,2
 BB     2,3

I want my result to be like:

Name   Order
 AA      1
 AA      2
 BB      2
 BB      3

How can I achieve this in Redshift?

Thanks!

Answer 1

Assuming that you know in advance the maximum number of elements per delimited list, you can do this with a table of numbers and split_part() :

select t.name, split_part(t.order, ',', n.n) val
from (
    select 1 n
    union all select 2
    union all select 3
) n
inner join mytable t
    on n.n <= regexp_count(t.order, ',') + 1

you can expand derived table n with more numbers as needed. It is also possible to use row_number() against a large table to generate the numbers table.