Modify Rails controller to work with Postgres/Heroku - ruby-on-rails

Question

I'm working my way through the railstutorial whilst working on my own mini project. Whilst it has been suggested that the development database you use should be the same as the one in production, the guide uses sqlite for development
and I've been doing the same.
I've deployed some changes recently, that work locally, to my app hosted on Heroku however, when trying to access a specific page, I receive the following error:
If you are the application owner check the logs for more information.
How can I access the logs that are mentioned?
I'm guessing a possible cause is due to the code in my controller that returns data from the db, and works in sqlite but is possibly invalid for postgres. Can someone please suggestion improvements for the controller.
I've attached my code below.
accounts_controller.rb:
# GET /accounts/1/history
def history
#account = Account.find(params[:id])
#accountHistory = Account.select("accounts.*, balances.*").joins("JOIN balances").where('balances.account_id = :accountId', {accountId: #account.id}).where('accounts.id = :accountId', {accountId: #account.id}).order('date desc')
end
history.html.erb
<tbody>
<% #accountHistory.each do |a| %>
<tr>
<td><%= date_format(a.date) %></td>
<td class='account-balance'><%= number_to_currency(a.balance, unit: "£") %></td>
</tr>
<% end %>
</tbody>
UPDATE:
Looking at the Heroku logs, it looks like there's a syntax error for Postgres. Can anyone suggest how to improve it?
heroku logs:
2015-12-22T16:54:39.361012+00:00 app[web.1]: Started GET "/accounts/3/history" for 2.220.200.172 at 2015-12-22 16:54:39 +0000
2015-12-22T16:54:39.370975+00:00 app[web.1]: Account Load (0.9ms) SELECT accounts.*, balances.* FROM "accounts" JOIN balances WHERE (balances.account_id = 3) AND (accounts.id = 3) ORDER BY date desc
2015-12-22T16:54:39.371012+00:00 app[web.1]: LINE 1: ...ounts.*, balances.* FROM "accounts" JOIN balances WHERE (bal...
2015-12-22T16:54:39.371010+00:00 app[web.1]: PG::SyntaxError: ERROR: syntax error at or near "WHERE"
2015-12-22T16:54:39.371013+00:00 app[web.1]: ^
2015-12-22T16:54:39.371015+00:00 app[web.1]: : SELECT accounts.*, balances.* FROM "accounts" JOIN balances WHERE (balances.account_id = 3) AND (accounts.id = 3) ORDER BY date desc
2015-12-22T16:54:39.371797+00:00 app[web.1]: Rendered accounts/history.html.erb within layouts/application (2.3ms)
2015-12-22T16:54:39.371929+00:00 app[web.1]: Completed 500 Internal Server Error in 6ms (ActiveRecord: 1.6ms)
2015-12-22T16:54:39.374155+00:00 app[web.1]:
2015-12-22T16:54:39.374158+00:00 app[web.1]: ActionView::Template::Error (PG::SyntaxError: ERROR: syntax error at or near "WHERE"

Answer 1

Looks like the Heroku error is related to the joins statement. It needs the on, which you can do a couple ways. To do this in an active relation, just change the joins statement from
.joins("JOIN balances")
To
.joins(:balances)
Note - this part may not be needed anymore
.where('balances.account_id = :accountId', {accountId: #account.id})
Looking at your code a little further, there may be something else you are really after. If accountHistory is a list of balance records, this would work for you....
#account = Account.find(params[:id])
#accountHistory = #account.balances
Or, to potentially do in one query...
#account = Account.includes(:balances).find(params[:id])
The balances collection is referenced on account, I suspect
class Account < ActiveRecord::Base
has_many :balances
end
And, with the foreign key on Balance
class Balance < ActiveRecord::Base
belongs_to :account
# Add a scope if you like to reuse code
scope :order_by_date, -> { order(:date => :desc) }
end
You can then reference balances easily. This is where Rails helps you out a lot to make things very readable.
#account.balances.order_by_date
You can assign this to #accountHistory if you want, or just refer to balances from the collection off account in the view which might look like:
<tbody>
<% #account.balances.order(:date => :desc).each do |b| %>
<tr>
<td><%= date_format(b.date) %></td>
<td class='account-balance'><%= number_to_currency(b.balance, unit: "£") %></td>
</tr>
<% end %>
</tbody>

Answer 2

Did you run heroku run rake db:migrate -a <YOUR HEROKU APP NAME> after you deployed to heroku?
If you did, you can check the logs they are referring to with:
heroku logs --tail -a <YOUR HEROKU APP NAME>
Replace the <YOUR HEROKU APP NAME> with the name on your heroku configs. If you don't know how to find that, go to the heroku.com dashboard and find it under settings.