create new sql column to get new value

Question

I have this transaction table how can I query to find if a person is a New Client,Returning-Member, Returning-Non-member. for instance id 1 is a new client when sequence = 1, They can only be a member/returning-member after a type(member) has been purchased for example id 1 and sequence 4 is a returning-Non-member because this is the first time they are buying a member. After that transaction seq 5 they are now a returning-member

while for id 2 never bought a member so first sequence will be new client but others will be returning-non-member until they buy a member.

Question

id	Type	Date	Sequence
1	Member	2021-02-24	4
1	product	2021-01-03	2
2	service	2022-04-21	5
1	product	2021-02-01	3
2	service	2022-02-16	3
1	Member	2022-02-03	6
1	Service	2021-10-23	5
2	product	2022-01-03	2
1	service	2020-12-16	1
2	product	2022-03-30	4
2	service	2021-12-01	1
1	Member	2022-04-03	7

Result

id	Type	Date	Sequence	New column
1	Member	2021-02-24	4	Returning-Non-member
1	product	2021-01-03	2	Returning-Non-member
2	service	2022-04-21	5	Returning-Non-member
1	product	2021-02-01	3	Returning-Non-Member
2	service	2022-02-16	3	Returning-Non-member
1	Member	2022-02-03	6	Returning-Member
1	Service	2021-10-23	5	Returning-Member
2	product	2022-01-03	2	Returning-Non-Member
1	service	2020-12-16	1	New Client
2	product	2022-03-30	4	Returning-Non-Member
2	service	2021-12-01	1	New Client
1	Member	2022-04-03	7	Returning-Member

Answer 1

You can do it in a pretty strait forward way with an additional subquery, but it's not the best way in terms of performance.

SELECT
    *,
    CASE 
        WHEN t.Sequence = 1 THEN 'New Client'
        WHEN 
            EXISTS (
                SELECT * 
                    FROM YourTable AS th 
                    WHERE 
                        th.Date < t.Date 
                        AND th.Id = t.Id 
                        AND th.Type ILIKE 'Member'
            ) THEN 'Returning-Member' 
        ELSE 'Returning-Non-Member'
    END AS Membership
    FROM YourTable AS t