Customers Who Never Order - LeetCode javascript solutions

Problem

Suppose that a website contains two tables, the Customers table and the Orders table. Write a SQL query to find all customers who never order anything.

Table: Customers.

+----+-------+
| Id | Name  |
+----+-------+
| 1  | Joe   |
| 2  | Henry |
| 3  | Sam   |
| 4  | Max   |
+----+-------+

Table: Orders.

+----+------------+
| Id | CustomerId |
+----+------------+
| 1  | 3          |
| 2  | 1          |
+----+------------+

Using the above tables as example, return the following:

+-----------+
| Customers |
+-----------+
| Henry     |
| Max       |
+-----------+

Solution 1

# Write your MySQL query statement below
select a.Name as Customers
  from Customers a
  where a.Id not in (
    select b.CustomerId from Orders b
  )

Explain:

nope.

Complexity:

Time complexity :
Space complexity :

Solution 2

# Write your MySQL query statement below
select a.Name as Customers
  from Customers a
  where not exists (
    select Id from Orders b where a.Id = b.CustomerId
  )

Explain:

nope.

Complexity:

Time complexity :
Space complexity :

Solution 3

# Write your MySQL query statement below
select a.Name as Customers
  from Customers a
  left join Orders b
  on a.Id = b.CustomerId
  where b.CustomerId is null

Explain:

nope.

Complexity:

Time complexity :
Space complexity :