task: #3451

Author: Ivanbyone

README.md

@@ -194,6 +194,7 @@ Useful for preparing for technical interviews and improving your SQL skills.
     - [185. Department Top Three Salaries](./leetcode/hard/185.%20Department%20Top%20Three%20Salaries.sql)
     - [601. Human Traffic of Stadium](./leetcode/hard/601.%20Human%20Traffic%20of%20Stadium.sql)
     - [3374. First Letter Capitalization II](./leetcode/hard/3374.%20First%20Letter%20Capitalization%20II.sql)
+    - [3451. Find Invalid IP Addresses](./leetcode/hard/3451.%20Find%20Invalid%20IP%20Addresses.sql)
 
 ## Contributing
 

leetcode/hard/3451. Find Invalid IP Addresses.sql

@@ -0,0 +1,39 @@
+/*
+Question 3451. Find Invalid IP Addresses
+Link: https://leetcode.com/problems/find-invalid-ip-addresses/description/?envType=problem-list-v2&envId=database
+
+Table:  logs
+
++-------------+---------+
+| Column Name | Type    |
++-------------+---------+
+| log_id      | int     |
+| ip          | varchar |
+| status_code | int     |
++-------------+---------+
+log_id is the unique key for this table.
+Each row contains server access log information including IP address and HTTP status code.
+Write a solution to find invalid IP addresses. An IPv4 address is invalid if it meets any of these conditions:
+
+Contains numbers greater than 255 in any octet
+Has leading zeros in any octet (like 01.02.03.04)
+Has less or more than 4 octets
+Return the result table ordered by invalid_count, ip in descending order respectively. 
+*/
+
+SELECT
+    ip,
+    COUNT(ip) AS invalid_count
+FROM logs
+WHERE 
+    ARRAY_LENGTH(STRING_TO_ARRAY(ip, '.'), 1) != 4
+    OR LEFT(SPLIT_PART(ip, '.', 1), 1) = '0'
+    OR LEFT(SPLIT_PART(ip, '.', 2), 1) = '0'
+    OR LEFT(SPLIT_PART(ip, '.', 3), 1) = '0'
+    OR LEFT(SPLIT_PART(ip, '.', 4), 1) = '0'
+    OR SPLIT_PART(ip, '.', 1)::numeric > 255
+    OR SPLIT_PART(ip, '.', 2)::numeric > 255
+    OR SPLIT_PART(ip, '.', 3)::numeric > 255
+    OR SPLIT_PART(ip, '.', 4)::numeric > 255
+GROUP BY ip
+ORDER BY invalid_count DESC, ip DESC