LeetCode MySQL-584. Find Customer Referee

    AllenLi
    LeetCode MySQL

    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.

    寫一個 SQL Query來報告，沒有被客戶 referee_id = 2 推薦的「name」，並回傳任意順序的結果。

    Table: Customer

    +-------------+---------+
| Column Name | Type    |
+-------------+---------+
| id          | int     |
| name        | varchar |
| referee_id  | int     |
+-------------+---------+
id is the primary key column for this table.
Each row of this table indicates the id of a customer, their name, and the id of the customer who referred them.

    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:
    1. 選擇標題「name」
    2. 來自於 Customer 的 table
    3. 設定條件「referee_id 不等於 2」
    (ex.注意需列入null的情況)

    Code.1:

    SELECT name
    FROM Customer
WHERE referee_id IS NULL OR referee_id != 2;

    Code.2:

    SELECT name
    FROM Customer
WHERE referee_id IS NULL OR referee_id <> 2;

    newCustomer

    Related Posts