Social timeline SQL logic - php

Question

I am not experienced with MySQL genius so pardon me. I have 2 tables,
TABLE 1 contains column names: post_id (int, Auto Increment), post (varchar, user posts) and like (int) {like is incremented when a user likes the post e.g similar to facebook likes}
TABLE 2 contains column name: id (int, Auto Increment) and post_id(int, foreign key to TABLE 1), user_id(varchar, User who liked this post)
Now here is the tricky part for me, I want to select all posts from TABLE 1 and also indicate to the user which post has already been liked through TABLE 2 when a user requests for timeline, thus preventing the user from liking the the post again e.g how likes works on Instagram or any other social network i.e unlike if already liked.
What I tried using PHP and MySQL: Basically I retrieved all post from TABLE 1 based on the user retrieving a timeline and then I retrieved all data from TABLE 2 based on the user who needs the timeline, then I check to see if there is a match with TABLE 1's returned data and TABLE 2's returned data. With each returned post in the timeline I tag 1 to indicate in code the incoming post has been liked and 0 for not liked and then I display the appropriate UI flow to user in doing so I can make sure the user does not like the same post twice.
Selecting all from TABLE 2
SELECT * FROM `TABLE_2` WHERE `username` = :username
Selecting from TABLE 1
SELECT * FROM `TABLE_1` WHERE `reporter` IN (SELECT `destination_id` FROM `followers` WHERE `source_id` = :username)
UNION
SELECT * FROM `TABLE_1` WHERE `reporter` = :username
ORDER BY `created_at` DESC LIMIT 20
The above query returns a users timeline based on another logic and certain other factors
Now I compare both returned data from TABLE 1 and TABLE 2
if($likes != NULL)
{
$count = 0;
foreach($returnedtimeline["posts"] as $single)
{
if(array_search($likes[$count], $single) == "id")
{
$returnedtimeline["posts"][$count]["liked"] = 1;
$count++;
}else{
$returnedtimeline["posts"][$count]["liked"] = 0;
$count++;
}
}
But I believe there is a better way I can do this through one direct query than multiple queries because my methods has large disadvantages with time, amount of data and processing power of the server.

Answer 1

I believe you just want join in your select, to return columns from both tables at once. Something like:
select
post_id,
case when "Table 2".post_id is null then 0 else 1 end as UserHasLiked
from "Table 1"
left join "Table 2" on "Table 1".post_id = "Table 2".post_id
I'm not a MYSQL user, so the syntax may be a little off, but it should be pretty close I think.

Answer 2

SELECT DISTINCT *,
CASE WHEN likes.face_id = persona.face_id THEN '1' ELSE '0' END liked,
CASE WHEN dislikes.face_id = persona.face_id THEN '1' ELSE '0' END disliked,
CASE WHEN comments.face_id = persona.face_id THEN '1' ELSE '0' END commented
FROM persona, likes, dislikes, comments
RIGHT JOIN tagged ON tagged.phone_id = :pid WHERE persona.face_id = tagged.face_id
works like magic.