sql help getting data from all the followers ? ( like twitter if we follow )

StackOverflow https://stackoverflow.com/questions/3596798

  •  02-10-2019
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Question

alt text

example if i have 

follow table
company one ( cid = 1 ) following two ( cid = 2 )
company one ( cid = 1 ) following three( cid = 3 )

feeds table
company one ( cid = 1 ) type 'product' description 'hello ive updated a product';
company two ( cid = 2 ) type 'product' description 'hello ive updated a product im from company 2';
company three ( cid = 3 ) type 'shoutout' description 'hello ive i got a shoutout im company 3';
company one ( cid = 1 ) type 'product' description 'hello ive updated my second product';

question

how do i get all the feeds.description from the company that my company ( example here is cid = 1 ) ?

heres my simple pdo sql to get just mine.

    $data['feeds']['cid'] = 1;

    return $this->db->fetchAll("SELECT feeds.type, feeds.$type, feeds.cid, feeds.time, companies.name FROM feeds, companies WHERE 
    feeds.cid = :cid AND companies.cid = :cid ORDER BY feeds.fid DESC LIMIT 0, 5", $data['feeds']);

this will display
hello ive updated a product
hello ive updated my second product

maybe something like this ? ( fail )

    $data['feeds']['cid'] = 1,2,3;

    return $this->db->fetchAll("SELECT feeds.type, feeds.$type, feeds.cid, feeds.time, companies.name FROM feeds, companies WHERE 
    feeds.cid = :cid AND companies.cid = :cid ORDER BY feeds.fid DESC LIMIT 0, 5", $data['feeds']);

this should be displaying like
hello ive updated a product
hello ive updated a product im from company 2
hello ive i got a shoutout im company 3
hello ive updated my second product

or simpler get feeds.description from each follow.following ( cid = 1,2,3,etc ) from me. ( cid = 1) or if twitter get all my friends status ( friends that i follow )

edit*

some good guys at irc mysql said to use joins. but i just dont get it. what i get is this

fetch all the follow.following from cid = me ( example cid = 1 )

then

SELECT * FROM feeds WHERE feeds.cid = IN (2,3,cid that im following ( see follow.following ))

anyone can give me an example for joins in this problem ?

Was it helpful?

Solution

So, assuming that the question is "How do i get all the feeds.description from the company that my company IS FOLLOWING?" you want to join using the following key:

select 
companies.name, 
feeds.type, 
feeds.description 
from follow 
inner join feeds on (follow.following = feeds.cid or follow.cid = feeds.cid)
inner join companies on (feeds.cid = companies.cid)
where follow.cid = :cid
order by feeds.fid desc 
limit 5;

This should list all of the companies that your :cid (1) is following.

EDIT: Feeds should include my company's feeds + feeds my company is following.

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