Question

I am new to web programming and I’m trying to make a twitter-clone. At this point, I have 3 tables:

users (id, name)

• id is the auto-generated id
• name of the user

tweets (id, content, user_id)

• id is the auto-generated id
• content is the text of the tweet
• user_id is the id of the user that made the post

followers (id, user_id, following_id)

• id is the auto-generated id
• user_id is the user who is doing the following
• following_id is the user that is being followed

So, being new to sql as well, I am trying to build an SQL statement that would return the tweets that the currently-logged in user and of everyone he follows.

I tried to use this statement, which works sometimes, but other times, I get an error that says “Subquery returns more than 1 row”. Here is the statement:

SELECT * FROM tweets 
WHERE user_id IN
((SELECT following_id FROM followers
WHERE user_id = 1),1) ORDER BY date DESC

• I put 1 as an example here, which would be the id of the currently logged-in user.

I haven’t had any luck with this statement; any help would be greatly appreciated! Thank you.

Answer 1

SELECT * 
FROM tweets 
WHERE 
  user_id IN (SELECT following_id FROM followers WHERE user_id = 1)
  OR user_id = 1
ORDER BY date DESC