Each row of this table indicates the id of a customer, their name, and the id of the customer who referred them.

Write an SQL query to report the names of the customer that are not referred by the customer with id = 2.

Return the result table in any order.

Return the result table in any order.

Examples

Example 1:

Input: Customer table:

+----+------+------------+
| id | name | referee_id |
+----+------+------------+
| 1  | Will | null       |
| 2  | Jane | null       |
| 3  | Alex | 2          |
| 4  | Bill | null       |
| 5  | Zack | 1          |
| 6  | Mark | 2          |
+----+------+------------+

Output:

+------+
| name |
+------+
| Will |
| Jane |
| Bill |
| Zack |
+------+

Solution

Method 1 - Simple Where

Code

[{"language":"SQL","code":"SELECT name \nFROM Customer\nWHERE referee_id != 2 OR referee_id IS NULL;","lang":"sql","html":"<pre class=\"shiki shiki-themes github-light github-dark\" style=\"background-color:#fff;--shiki-dark-bg:#24292e;color:#24292e;--shiki-dark:#e1e4e8\" tabindex=\"0\"><code><span class=\"line\"><span style=\"color:#D73A49;--shiki-dark:#F97583\">SELECT</span><span style=\"color:#D73A49;--shiki-dark:#F97583\"> name</span><span style=\"color:#24292E;--shiki-dark:#E1E4E8\"> </span></span>\n<span class=\"line\"><span style=\"color:#D73A49;--shiki-dark:#F97583\">FROM</span><span style=\"color:#24292E;--shiki-dark:#E1E4E8\"> Customer</span></span>\n<span class=\"line\"><span style=\"color:#D73A49;--shiki-dark:#F97583\">WHERE</span><span style=\"color:#24292E;--shiki-dark:#E1E4E8\"> referee_id </span><span style=\"color:#D73A49;--shiki-dark:#F97583\">!=</span><span style=\"color:#005CC5;--shiki-dark:#79B8FF\"> 2</span><span style=\"color:#D73A49;--shiki-dark:#F97583\"> OR</span><span style=\"color:#24292E;--shiki-dark:#E1E4E8\"> referee_id </span><span style=\"color:#D73A49;--shiki-dark:#F97583\">IS</span><span style=\"color:#D73A49;--shiki-dark:#F97583\"> NULL</span><span style=\"color:#24292E;--shiki-dark:#E1E4E8\">;</span></span></code></pre>"}]

Method 2 - Using IFNULL OR Coelesce in Where

Code

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