1. Chuyển chuỗi sang dạng cột để select
select regexp_substr('PRIM,SECO,THIRD,NORIGHT','[^,]+', 1, level) as code_id from dual connect by regexp_substr('PRIM,SECO,THIRD,NORIGHT', '[^,]+', 1, level) is not null;
select regexp_substr('PRIM,SECO,THIRD,NORIGHT','[^,]+', 1, level) as code_id from dual connect by regexp_substr('PRIM,SECO,THIRD,NORIGHT', '[^,]+', 1, level) is not null;