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postgresql return 0 if returned value is null
...ns the first of its arguments that is not null.
Null is returned only if all arguments are null. It is often
used to substitute a default value for null values when data is
retrieved for display.
Edit
Here's an example of COALESCE with your query:
SELECT AVG( price )
FROM(
SELECT *, cum...
Android Studio IDE: Break on Exception
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To break on all exceptions, caught or uncaught:
Open the Breakpoints window via Run -> View Breakpoints.
The Breakpoints dialog appears. In the left pane, scroll to the bottom. Select Any exception under Java Exception Breakpoints
W...
Can I arrange repositories into folders on Github?
I am new to git and what I am doing now is to upload all my recent projects as repositories to github. There are a lot of different projects like webdesign, wordpress themes and different types of applications. And some of these also belong to bigger projects because they were about testing some stu...
Underscore vs Double underscore with variables and methods [duplicate]
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Explanation:
People coming from a C++/Java background are especially prone to
overusing/misusing this "feature". But __private names don't work the
same way as in Java or C++. They just trigger a name mangling whose
purpose is to prevent accidental namespace collisions in subclasses...
Get exception description and stack trace which caused an exception, all as a string
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See the traceback module, specifically the format_exc() function. Here.
import traceback
try:
raise ValueError
except ValueError:
tb = traceback.format_exc()
else:
tb = "No error"
finally:
print tb
...
Why do we use $rootScope.$broadcast in AngularJS?
... scope of that app can catch it using a simple: $scope.$on().
It is especially useful to send events when you want to reach a scope that is not a direct parent (A branch of a parent for example)
!!! One thing to not do however is to use $rootScope.$on from a controller. $rootScope is the applicati...
List files in local git repo?
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This command:
git ls-tree --full-tree -r --name-only HEAD
lists all of the already committed files being tracked by your git repo.
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git -> show list of files changed in recent commits in a specific directory
...n. If you need a comprehensive list of commits, try making the number unusually large, like -1000 or more as needed.
– Julian Soro
Jan 8 '15 at 20:07
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Memcache(d) vs. Varnish for speeding up 3 tier web architecture
...ache will provide info for pages that have a mixture of known and new data allowing you to generate pages faster.
An example that could apply to stackoverflow.com: adding this comment invalidated the page cache, so this page would have to be cleared from Varnish (and also my profile page, which pr...
Why is an int in OCaml only 31 bits?
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This is called a tagged pointer representation, and is a pretty common optimization trick used in many different interpreters, VMs and runtime systems for decades. Pretty much every Lisp implementation uses them, many Smalltalk VMs, m...