Tricky CTE - recursive sql (editing my query)

Question

I want to edit my query in order to get something a little more ticky.

The goal is to obtain the approval workflow for every customer, displaying that information in thi

Answer 1

I tried.
And normalized a bit extra, adding a chains table.

Here's my attempt :

create table entity_types 
(
 entity_type_id int primary key, 
 entity_type_name varchar(32) not null
);

✓

create table relation_types 
(
 relation_type_id int primary key, 
 relation_type_name varchar(32) not null
);

✓

create table chains 
(
 chain_id int primary key,
 chain_name varchar(30) not null
);

✓

create table entities 
(
 entity_id int primary key,
 entity_name varchar(32) not null, 
 entity_type_id int not null,
 chain_id int,
 foreign key (entity_type_id)
         references entity_types(entity_type_id),
 foreign key (chain_id)
         references chains(chain_id)
);

✓

create table relationships 
(
 relationship_id int primary key, 
 relation_type_id int not null,
 entity_id_1 int not null,
 entity_id_2 int not null,
 foreign key (relation_type_id)
         references relation_types(relation_type_id)
);

✓

create table entity_chains 
(
 entity_id int not null,
 chain_id int not null,
 primary key (entity_id, chain_id),
 foreign key (chain_id)
         references chains(chain_id),
 foreign key (entity_id) 
         references entities(entity_id)
);

✓

INSERT INTO entity_types
(entity_type_id, entity_type_name) VALUES
(308,'CLIENT'),
(309,'APPROVER1'),
(310,'APPROVER2'),
(311,'APPROVER3'),
(312,'J3 APPROVER4'),
(313,'J4 APPROVER4'),
(314,'J5 APPROVER4'),
(315,'J6 APPROVER4'),
(316,'J7 APPROVER4');

✓

INSERT INTO relation_types
(relation_type_id, relation_type_name) VALUES
(444,'J6 CLIENT-APPROVER4'),
(445,'J3 CLIENT-APPROVER4'),
(446,'J4 CLIENT-APPROVER4'),
(447,'J10 CLIENT-APPROVER4'),
(448,'J4 CLIENT-APPROVER4'),
(449,'J5 CLIENT-APPROVER4'),
(450,'J10 CLIENT-APPROVER4'),
(451,'J3 CLIENT-APPROVER4'),
(452,'J8 CLIENT-APPROVER4'),
(453,'J5 CLIENT-APPROVER4'),
(454,'J6 CLIENT-APPROVER4'),
(455,'J7 CLIENT-APPROVER4'),
(456,'J7 CLIENT-APPROVER4'),
(457,'J8 CLIENT-APPROVER4'),
(458,'CLIENT-APPROVER3'),
(459,'CLIENT-APPROVER1'),
(460,'APPROVER1-APPROVER2'),
(461,'APPROVER1-APPROVER3'),
(462,'J3 APPROVER1-APPROVER4'),
(463,'APPROVER2-APPROVER3'),
(464,'J3 APPROVER3-APPROVER4'),
(465,'J4 APPROVER3-APPROVER4'),
(466,'J5 APPROVER3-APPROVER4'),
(467,'J6 APPROVER3-APPROVER4'),
(468,'J7 APPROVER3-APPROVER4'),
(469,'J8 APPROVER3-APPROVER4'),
(470,'J10 APPROVER3-APPROVER4'),
(471,'CLIENT-APPROVER2');

✓

insert into chains 
(chain_id, chain_name) values
(45,'Chain1'),
(46,'Chain2');

✓

INSERT INTO entities 
(entity_id, entity_name, 
 entity_type_id, chain_id) VALUES
(12, 'Math Andrew', 308, 45),
(13, 'John Connor', 308, 46),
(18, 'ZATCH', 309, null),
(19, 'MAX', 309, null),
(20, 'Ger',310, null),
(21, 'Mar',310, null),
(22, 'Maxwell',311, null),
(23, 'Ryan',312, null),
(24, 'Juy',313, null),
(25, 'Angel',314, null),
(26, 'John',315, null);

✓

INSERT INTO relationships 
(relationship_id, relation_type_id,
 entity_id_1, entity_id_2) VALUES
(787,459,12,18),
(788,460,18,20),
(789,463,20,21),
(790,467,21,26);

✓

insert into entity_chains 
(entity_id, chain_id) values
(12, 45),
(12, 46),
(13, 45),
(13, 46);

✓

WITH RECURSIVE RCTE AS
(
  SELECT
   ent.chain_id,
   entch.entity_id as entity_id_0,
   0 as lvl,
   0 as entity_id_1,
   entch.entity_id as entity_id_2,
   0 as relation_type_id
  FROM entities ent
  JOIN entity_chains entch
    ON entch.chain_id = ent.chain_id

  UNION ALL

  SELECT 
  cte.chain_id,
  cte.entity_id_0,
  lvl+1,
  rel.entity_id_1,
  rel.entity_id_2,
  rel.relation_type_id
  FROM RCTE cte
  JOIN relationships rel
    ON rel.entity_id_1 = cte.entity_id_2
),
CTE AS
(
  SELECT
  rcte.*,
  chains.chain_name,
  ent0.entity_name as entity_name_0,
  -- reltype.relation_type_name,
  -- enttype2.entity_type_name as entity_type_name_2,
  -- ent1.entity_name as entity_name_1,
  ent2.entity_name as entity_name_2
  FROM RCTE rcte
  JOIN chains ON chains.chain_id = rcte.chain_id
  JOIN entities ent0 ON ent0.entity_id = rcte.entity_id_0
  JOIN entities ent2 ON ent2.entity_id = rcte.entity_id_2
  -- LEFT JOIN entity_types enttype2 ON enttype2.entity_type_id = ent2.entity_type_id
  -- LEFT JOIN relation_types reltype ON reltype.relation_type_id = rcte.relation_type_id
  -- LEFT JOIN entities ent1 ON ent1.entity_id = rcte.entity_id_1
)
/*
SELECT * FROM CTE WHERE lvl > 0
ORDER BY chain_name, entity_id_0, lvl;
*/
SELECT 
REPLACE(CONCAT(entity_name_0,'-',chain_name),' ','') as chain_client,
max(case when lvl=1 then entity_name_2 end) as approver1,
max(case when lvl=2 then entity_name_2 end) as approver2,
max(case when lvl=3 then entity_name_2 end) as approver3,
max(case when lvl=4 then entity_name_2 end) as approver4
FROM CTE cte
WHERE lvl > 0
GROUP BY chain_name, entity_name_0
ORDER BY chain_client;

chain_client      | approver1 | approver2 | approver3 | approver4
:---------------- | :-------- | :-------- | :-------- | :--------
MathAndrew-Chain1 | ZATCH     | Ger       | Mar       | John     
MathAndrew-Chain2 | ZATCH     | Ger       | Mar       | John     

db<>fiddle here