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Question
Formatted question description: https://leetcode.ca/all/1683.html
1683. Invalid Tweets
SQL Schema
Table: Tweets
+----------------+---------+
| Column Name | Type |
+----------------+---------+
| tweet_id | int |
| content | varchar |
+----------------+---------+
tweet_id is the primary key for this table.
This table contains all the tweets in a social media app.
Write an SQL query to find the IDs of the invalid tweets.
The tweet is invalid if the number of characters used in the content of the tweet is strictly greater than 15.
Return the result table in any order.
The query result format is in the following example:
Tweets table:
+----------+----------------------------------+
| tweet_id | content |
+----------+----------------------------------+
| 1 | Vote for Biden |
| 2 | Let us make America great again! |
+----------+----------------------------------+
Result table:
+----------+
| tweet_id |
+----------+
| 2 |
+----------+
Tweet 1 has length = 14. It is a valid tweet.
Tweet 2 has length = 32. It is an invalid tweet.
Algorithm
There are two functions for calculating the length of a field in MySQL:
- LENGTH: A built-in function to obtain the length of a string, one Chinese character is counted as three characters, and a number or letter is counted as one character
- CHAR_LENGTH: Regardless of whether Chinese characters, numbers or letters, they are all regarded as a character
Code
SQL
SELECT tweet_id
FROM Tweets
WHERE LENGTH(content) > 15;