Checking the Length of a String in a MySQL Where Clause

Let's say we have a SQL schema like this:

Create table If Not Exists Tweets(tweet_id int, content varchar(50));
Truncate table Tweets;
insert into Tweets (tweet_id, content) values ('1', 'Vote for Biden');
insert into Tweets (tweet_id, content) values ('2', 'Let us make America great again!');

This will give us the following table:

tweet_id	content
1	Vote for Biden
2	Let us make America great again!

If we wanted to select only the tweet_id's where the content length is greater than 15, we can use CHAR_LENGTH() in a WHERE clause.

SELECT tweet_id
FROM Tweets
WHERE CHAR_LENGTH(content) > 15;

tweet_id
2

Note that you can also use LENGTH() rather than CHAR_LENGTH, although CHAR_LENGTH() is more appropriate here. LENGTH() gets the length of the value in bytes, whereas CHAR_LENGTH() gets the length of the value in characters.

SELECT tweet_id
FROM Tweets
WHERE LENGTH(content) > 15;

tweet_id
2

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Checking the Length of a String in a MySQL Where Clause