Question

I have the following “tweets” table:

tweet_id  user_id  text
---------------------------------------------------
1         2        this is a tweet with (TAG} in it
2         2        tweet without a TAG
3         2        {TAG} another {TAG} tweet
4         4        look at my {TAG} and weep!

I want to count, for each user, the number of tweets that contains {TAG} at least once. The tag could be anywhere in the tweet: at the beginning, in the middle or at the end (read: not followed by a space or anything). The table has millions of records, so I’m looking for an efficient way to do this. My first attempt was

SELECT COUNT(tweet_id) FROM tweets WHERE `text` LIKE '%{TAG}%' AND user_id = 2

but this returns 0 while, in this example, it was expected to return 2. So two questions: (i) what am I doing wrong and (ii) is there a more efficient way to do this?

[EDIT]

I would like to insert the result into the “users” table:

user_id  tweets_with_tag
2        2
3        0
4        9

Is it possible to count and insert in the same query?

Answer 1

To Insert:

INSERT INTO users(user_id, tweets_with_tag) 
SELECT COUNT(tweet_id) as 'tweets_with_tag',
[user_id] as 'user_id'
FROM tweets 
WHERE text LIKE '%{TAG}%'
GROUP BY user_id

Edit: If the User table already exists do the following

UPDATE users
SET tweets_with_tag = (
    SELECT COUNT(tweet_id) as 'tweets_with_tag'
    FROM tweets 
    WHERE text LIKE '%{TAG}%' and user_id = users.user_id
    GROUP BY user_id)