coder-xiaomo/leetcode-problemset
1
0
Fork 0
mirror of https://gitee.com/coder-xiaomo/leetcode-problemset synced 2025-09-13 11:21:42 +08:00
Code Issues Projects Releases Wiki Activity GitHub Gitee

update

Browse Source
This commit is contained in:
小墨
2022-03-29 12:55:24 +08:00
parent 2b0511d272
commit b84ae535b7
3973 changed files with 51044 additions and 105065 deletions
Download Patch File Download Diff File Expand all files Collapse all files

54
leetcode/problem/the-latest-login-in-2020.html Normal file
View File

@@ -0,0 +1,54 @@
<p>Table: <code>Logins</code></p>
<pre>
+----------------+----------+
| Column Name | Type |
+----------------+----------+
| user_id | int |
| time_stamp | datetime |
+----------------+----------+
(user_id, time_stamp) is the primary key for this table.
Each row contains information about the login time for the user with ID user_id.
</pre>
<p>&nbsp;</p>
<p>Write an SQL query to report the <strong>latest</strong> login for all users in the year <code>2020</code>. Do <strong>not</strong> include the users who did not login in <code>2020</code>.</p>
<p>Return the result table <strong>in any order</strong>.</p>
<p>The query result format is in the following example.</p>
<p>&nbsp;</p>
<p><strong>Example 1:</strong></p>
<pre>
<strong>Input:</strong>
Logins table:
+---------+---------------------+
| user_id | time_stamp |
+---------+---------------------+
| 6 | 2020-06-30 15:06:07 |
| 6 | 2021-04-21 14:06:06 |
| 6 | 2019-03-07 00:18:15 |
| 8 | 2020-02-01 05:10:53 |
| 8 | 2020-12-30 00:46:50 |
| 2 | 2020-01-16 02:49:50 |
| 2 | 2019-08-25 07:59:08 |
| 14 | 2019-07-14 09:00:00 |
| 14 | 2021-01-06 11:59:59 |
+---------+---------------------+
<strong>Output:</strong>
+---------+---------------------+
| user_id | last_stamp |
+---------+---------------------+
| 6 | 2020-06-30 15:06:07 |
| 8 | 2020-12-30 00:46:50 |
| 2 | 2020-01-16 02:49:50 |
+---------+---------------------+
<strong>Explanation:</strong>
User 6 logged into their account 3 times but only once in 2020, so we include this login in the result table.
User 8 logged into their account 2 times in 2020, once in February and once in December. We include only the latest one (December) in the result table.
User 2 logged into their account 2 times but only once in 2020, so we include this login in the result table.
User 14 did not login in 2020, so we do not include them in the result table.
</pre>