Noooob question (2 days ruby experience 
I have a plugin almost doing what I want but have a hang up here:
posts = Post.where('user_id = ? and post_number = ?', params["uid"], params["tid"])
.order(created_at: :desc)
.limit(params["total"])
I’ve tried a number of versions. but they all case errors .
It feels more like a query issues than syntax but I bow before the experts edu-mecate me.
so good of you to ask, and admittedly that helped… 
BUT perhaps you can assist further with my query! The issue was the input value
while I can do
ok
Post.where('user_id: '1,2') #works
Post.where('topic_id: '4,5') #works
Fails
Post.where('user_id = ? or topic_id = ?', '1,2', '4, 5') #fails!
So again I assume! I’ll need to iterate over each user id, but… NOOOOB (assistance greatly appreciated!
So why did it fail? What is the error that was raised when you ran the code? 
Boom! (thanks BTW )
ActiveRecord::StatementInvalid (PG::InvalidTextRepresentation: ERROR: invalid input syntax for integer: "1,2"
LINE 1: ...ERE ("posts"."deleted_at" IS NULL) AND (user_id = '1,2' or t...
^
: SELECT "posts".* FROM "posts" WHERE ("posts"."deleted_at" IS NULL) AND (user_id = '1,2' or topic_id = '4') ORDER BY "posts"."created_at" DESC LIMIT 30)
/var/lib/gems/2.2.0/gems/rack-mini-profiler-0.9.9.2/lib/patches/db/pg.rb:93:in `exec'
Try Post.where(user_id IN (?) OR topic_id IN (?), [1,2], [4,5])
So if I say post.where() it causes a error?
@tgxworld Thanks that helped a bunch.
For the record I was doing a bunch of stuff that I SHOULD have known better…
- not splitting the string to an actual array (duh facepalm )
- your request seems to have fix the syntax issues (woot)
final code
uid = params["uid"].split(",")
tid = params["tid"].split(",")
posts = Post.where('user_id IN (?) OR topic_id IN (?)', uid, tid )
.order(created_at: :desc)
.limit(params["total"])
.offset(params["start"])
obj = {follow_posts: posts }
render json: obj
Massive thanks!! 