Classify column on the basis of sequence and patterns

Question

I have a column Id in a PostgreSQL table ABC.

Id is a bigint of length 10 (minLength=maxLength=10)

I have to write a SQL query and classify Id as:

• Any Id that commences with exactly 3 consecutive odd digits and concludes with at least 2 consecutive even digits is classified as “TYPE A”;
• Any Id where the second digit is greater than 6 or the third character is less than or equal to 4 is classified as “TYPE B”;
• Any odd-numbered Id is classified as “TYPE C” unless it ends in 7;
• Any even-numbered Id is classified as “TYPE D” unless it ends in 2;
• All other Id are classified as “TYPE X”;

Answer 1

Each type can be found with a regular expression.

create table ABC (
 Id decimal(10) primary key check(length(Id::text)=10)
);

insert into ABC (Id) values
  (1350000042)
, (1640000000)
, (1090000503)
, (1294567890)
, (1090000907)
, (1090000902)

/*
Type A: Any Id that commences with exactly 3 consecutive odd digits
        and concludes with at least 2 consecutive even digits;
Type B: Any Id where the second digit is greater than 6 
        or the third character is less than or equal to 4;
Type C: Any odd-numbered Id unless it ends in 7;
Type D: Any even-numbered Id unless it ends in 2;
Type X: All other Id;
*/
select Id
, case
  when Id::text ~ '^[13579]{3}[02468].*[02468]{2}$' then 'A'
  when Id::text ~ '^(.[7-9]|..[0-4])' then 'B'
  when Id::text ~ '[1359]$' then 'C'
  when Id::text ~ '[0468]$' then 'D'
  else 'X'
  end as Type
from ABC
order by Type

        id | type
---------: | :---
1350000042 | A   
1760000000 | B   
1640000000 | B   
1090000503 | C   
1294567890 | D   
1090000907 | X   
1090000902 | X   

db<>fiddle here