Splitting up data from one table to another - sql

Question

Currently I have a table like shown in T1 that I'd like to split up into individual Person table like T2 and a PersonClientLink table like T3. Each relationship is stored as its own unique ID in T1. This makes duplicates of the same person and their clients which is making this difficult. I need to group the Persons from T1 into a single ID and basically turn it into T2 and create links for each relationship they have into T3. T3 Currently exists but is empty, I want to populate T3 based on the data in T1 first and then turn T1 into T2. Any advice would be appreciated :)
T1 - Current mess
ID
Client_Id
Name
1
5
Bob
2
6
Bob
3
7
Greg
4
8
Greg
T2 - Person
ID
Name
1
Bob
2
Greg
T3 - PersonClientLink
ID
Person_Id
Client_Id
1
1
5
2
1
6
3
2
7
4
2
8
I'm honestly clueless no idea where to begin with this...

Answer 1

I would create the T2 and T3 tables and populate them from T1. I would then drop T1 afterwards. The following is done with postgresql, but it should be the same. A serial column in postgresql is the same as an identity column in sqlserver.
create table t2 (id serial primary key,
name varchar(32) not null);
create table t3 (id serial primary key,
person_id integer not null,
client_id integer not null);
Create a foreign key from t3.person_id to t2.id
Populate t2 and t3:
insert into t2 (name) (select distinct name from t1);
insert into t3 (person_id,client_id) (
select t2.id,t1.client_id from t1,t2 where t2.name = t1.name);
Convert the join of the tables to ANSI style if sqlserver requires that.
The initial data (same as yours) and the results:
select * from t1;
id | client_id | name
----+-----------+------
1 | 5 | bob
2 | 6 | bob
3 | 7 | greg
4 | 6 | greg
(4 rows)
select * from t2;
id | name
----+------
1 | bob
2 | greg
(2 rows)
select * from t3;
id | person_id | client_id
----+-----------+-----------
1 | 1 | 6
2 | 1 | 5
3 | 2 | 6
4 | 2 | 7
(4 rows)
I hope this helps.