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Postgresql aggregate array
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Use array_agg: http://www.sqlfiddle.com/#!1/5099e/1
SELECT s.name, array_agg(g.Mark) as marks
FROM student s
LEFT JOIN Grade g ON g.Student_id = s.Id
GROUP BY s.Id
By the way, if you are using Postgres 9.1, you do...
AngularJS $http, CORS and http authentication
Because using CORS and http authentication with AngularJS can be tricky I edited the question to share one learned lesson. First I want to thank igorzg. His answer helped me a lot. The scenario is the following: You want to send POST request to a different domain with AngularJS $http service. There ...
How to check if std::map contains a key without doing insert?
The only way I have found to check for duplicates is by inserting and checking the std::pair.second for false , but the problem is that this still inserts something if the key is unused, whereas what I want is a map.contains(key); function.
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Why doesn't Haskell's Prelude.read return a Maybe?
Is there a good reason why the type of Prelude.read is
5 Answers
5
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How to add 10 days to current time in Rails
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Use
Time.now + 10.days
or even
10.days.from_now
Both definitely work. Are you sure you're in Rails and not just Ruby?
If you definitely are in Rails, where are you trying to run this from? Note that Active Support has...
Friend declaration in C++ - difference between public and private
Is there a difference between declaring a friend function/class as private or public? I can't seem to find anything about this online.
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Where is Vagrant saving changes to the VM?
I am just starting with Vagrant and I am having a little trouble understanding a few details. I have read through the docs but still am missing a basic concept. When I want to start a Vagrant box I run:
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R - Markdown avoiding package loading messages
I have been using Knitr via R-Studio, and think it is pretty neat. I have a minor issue though. When I source a file in an R-Chunk, the knitr output includes external comments as follows:
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AngularJS: disabling all form controls between submit and server response
I have a dilemma about what is the best (and correct) approach if I want to disable form controls (or at least make them unavailable for user interaction) during a period of time when user clicks sort of "Save" or "Submit" button and data travelling over the wire. I don't want to use JQuery (which i...
Escaping regex string
I want to use input from a user as a regex pattern for a search over some text. It works, but how I can handle cases where user puts characters that have meaning in regex?
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