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how to exclude null values in array_agg like in string_agg using postgres?
... non_canonical_users
FROM groups g
GROUP BY g.id
) s
Or, simpler and may be cheaper, using array_to_string which eliminates nulls:
SELECT
g.id,
array_to_string(
array_agg(CASE WHEN g.canonical = 'Y' THEN g.users ELSE NULL END)
, ','
) canonical_users,
array...
Can you do greater than comparison on a date in a Rails 3 search?
... also convert everything into the SQL notation
Note.
where("user_id = ? AND notetype = ? AND date > ?", current_user.id, p[:note_type], p[:date]).
order('date ASC, created_at ASC')
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Sequence contains no elements?
...
Put a breakpoint on that line, or a Debug.Print before it, in both cases and see what ID contains.
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how to add records to has_many :through association in rails
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@Mischa how should i handle error if House.find(params[:house_id]) is nill.. i got error of TypeMismatch if params[:house_id] is nil.. i already using rescue. but is there any better_way..??
– Vishal
Jul 30...
How can I shift-select multiple checkboxes like GMail?
...user can click on one checkbox in the email list, hold down the Shift key, and select a second checkbox. The JavaScript will then select/unselect the checkboxes that are between the two checboxes.
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SQL UPDATE SET one column to be equal to a value in a related table referenced by a different column
...QuestionAnswers a
on q.AnswerID = a.AnswerID
where q.QuestionID is null -- and other conditions you might want
I recommend to check what the result set to update is before running the update (same query, just with a select):
select *
from QuestionTrackings q
inner join QuestionAnswers a
on q.Answ...
Send message to specific client with socket.io and node.js
I'm working with socket.io and node.js and until now it seems pretty good, but I don't know how to send a message from the server to an specific client, something like this:
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ITunes review URL and iOS 7 (ask user to rate our app) AppStore show a blank page
Does anybody knows if the technique used to ask the user to rate our app and open for him the App Store directly on the rating page is still working on iOS 7 ?
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Django optional url parameters
...to rename the product kwarg to product_id, you only have to change line 4, and it will affect the below URLs.
Edited for Django 1.8 and above
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How are the points in CSS specificity calculated
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Pekka's answer is practically correct, and probably the best way to think about the issue.
However, as many have already pointed out, the W3C CSS recommendation states that "Concatenating the three numbers a-b-c (in a number system with a large base) gives the sp...