Question

1747. Leetflex Banned Accounts

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Description

Table: LogInfo

+-------------+----------+
| Column Name | Type   |
+-------------+----------+
| account_id  | int    |
| ip_address  | int    |
| login     | datetime |
| logout    | datetime |
+-------------+----------+
This table may contain duplicate rows.
The table contains information about the login and logout dates of Leetflex accounts. It also contains the IP address from which the account was logged in and out.
It is guaranteed that the logout time is after the login time.

 

Write a solution to find the account_id of the accounts that should be banned from Leetflex. An account should be banned if it was logged in at some moment from two different IP addresses.

Return the result table in any order.

The result format is in the following example.

 

Example 1:

Input: 
LogInfo table:
+------------+------------+---------------------+---------------------+
| account_id | ip_address | login         | logout        |
+------------+------------+---------------------+---------------------+
| 1      | 1      | 2021-02-01 09:00:00 | 2021-02-01 09:30:00 |
| 1      | 2      | 2021-02-01 08:00:00 | 2021-02-01 11:30:00 |
| 2      | 6      | 2021-02-01 20:30:00 | 2021-02-01 22:00:00 |
| 2      | 7      | 2021-02-02 20:30:00 | 2021-02-02 22:00:00 |
| 3      | 9      | 2021-02-01 16:00:00 | 2021-02-01 16:59:59 |
| 3      | 13     | 2021-02-01 17:00:00 | 2021-02-01 17:59:59 |
| 4      | 10     | 2021-02-01 16:00:00 | 2021-02-01 17:00:00 |
| 4      | 11     | 2021-02-01 17:00:00 | 2021-02-01 17:59:59 |
+------------+------------+---------------------+---------------------+
Output: 
+------------+
| account_id |
+------------+
| 1      |
| 4      |
+------------+
Explanation: 
Account ID 1 --> The account was active from "2021-02-01 09:00:00" to "2021-02-01 09:30:00" with two different IP addresses (1 and 2). It should be banned.
Account ID 2 --> The account was active from two different addresses (6, 7) but in two different times.
Account ID 3 --> The account was active from two different addresses (9, 13) on the same day but they do not intersect at any moment.
Account ID 4 --> The account was active from "2021-02-01 17:00:00" to "2021-02-01 17:00:00" with two different IP addresses (10 and 11). It should be banned.

Solutions

Solution 1: Self-Join

We can use a self-join to find out the cases where each account logs in from different IP addresses on the same day. The conditions for joining are:

• The account numbers are the same.
• The IP addresses are different.
• The login time of one record is within the login-logout time range of another record.

# Write your MySQL query statement below
SELECT DISTINCT
  a.account_id
FROM
  LogInfo AS a
  JOIN LogInfo AS b
    ON a.account_id = b.account_id
    AND a.ip_address != b.ip_address
    AND a.login BETWEEN b.login AND b.logout;