So, Supabase doesn't have a built-in way to handle hierarchical data directly. It's mainly a relational database system, so it doesn't support hierarchical data natively. But don't worry, you can still achieve it by creating multiple tables and setting up relationships between them.

Let's say we want to store employee data in a hierarchical way. Imagine a CEO leading department heads, who lead managers, who then lead subordinates. To do this, we need two tables: Employee and Hierarchy.

CREATE TABLE Employee (
   Id INT PRIMARY KEY,
   Name VARCHAR(100)
);

CREATE TABLE Hierarchy (
   EmployeeId INT,
   SupervisorId INT,
   FOREIGN KEY (EmployeeId) REFERENCES Employee(Id),
   FOREIGN KEY (SupervisorId) REFERENCES Employee(Id)
);

In the Employee table, each employee gets a unique Id. The Hierarchy table sets up who supervises whom.

Let's say our organization looks like this: CEO (John) -> Department Head (David) -> Manager (Lucy) -> Subordinate (Liam). We can insert these values into the tables like this:

INSERT INTO Employee (Id, Name)
VALUES 
   (1, 'John'),   --CEO 
   (2, 'David'),  --Department Head 
   (3, 'Lucy'),   --Manager 
   (4, 'Liam');   --Subordinate 

INSERT INTO Hierarchy (EmployeeId, SupervisorId)
VALUES 
   (2, 1),    --David is supervised by John 
   (3, 2),    --Lucy is supervised by David 
   (4, 3);    --Liam is supervised by Lucy

To get the whole hierarchy leading to a particular employee, we can use recursive queries. This is where it gets a bit fun!

WITH RECURSIVE employee_path AS (
   SELECT 
      e1.Name, 
      e2.Name AS Supervisor,
      CONCAT(e2.Name, '->', e1.Name) AS HierarchyChain
   FROM 
      Employee e1
      INNER JOIN Hierarchy h ON e1.Id = h.EmployeeId
      INNER JOIN Employee e2 ON h.SupervisorId = e2.Id
   WHERE 
      e1.Name = 'Liam'    --We are finding hierarchy for Liam
      
   UNION ALL
   
   SELECT 
      e1.Name, 
      e2.Name,
      CONCAT(e2.Name, '->', e_.HierarchyChain)
   FROM 
      Employee e1
      INNER JOIN Hierarchy h ON e1.Id = h.EmployeeId
      INNER JOIN Employee e2 ON h.SupervisorId = e2.Id
      INNER JOIN employee_path e_ ON e2.Name = e_._Supervisor
)

SELECT 
   *
FROM 
   employee_path;

Running this query will show the full hierarchy, like John -> David -> Lucy -> Liam. This example demonstrates how to handle hierarchical structures in Supabase by forming relationships between tables.

Oh, and a quick note: Always sanitize your inputs when using SQL queries to prevent SQL injections. Make sure your database enforces referential integrity constraints on foreign keys. If not, you might end up with orphan records, which can be a real headache!