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Counting null and non-null values in a single query
... able to get it to work on another RDBMS):
select sum(case when a is null then 1 else 0 end) count_nulls
, count(a) count_not_nulls
from us;
Or:
select count(*) - count(a), count(a) from us;
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How To Set Up GUI On Amazon EC2 Ubuntu server
...mod -aG admin awsgui
sudo vim /etc/ssh/sshd_config # edit line "PasswordAuthentication" to yes
sudo /etc/init.d/ssh restart
Setting up ui based ubuntu machine on AWS.
In security group open port 5901. Then ssh to the server instance. Run following commands to install ui and vnc server:
sudo ap...
What is “entropy and information gain”?
...ction should satisfy
if the probability of the event is 1 (predictable), then the function gives 0
if the probability of the event is close to 0, then the function should give high number
if probability 0.5 events happens it give one bit of information.
One natural measure that satisfy the const...
How do I Geocode 20 addresses without receiving an OVER_QUERY_LIMIT response?
...s, I get an OVER_QUERY_LIMIT unless I time them to be ~1 second apart, but then it takes 20 seconds before my markers are all placed.
...
Write a program to find 100 largest numbers out of an array of 1 billion numbers
... expressed as:
(k time to generate the queue with the first k elements, then n-k comparisons, and the expected number of insertions as described above, each takes an average log(k)/2 time)
Note that when N is very large comparing to K, this expression is a lot closer to n rather than NlogK. This...
What's the difference between the various methods to get a Context?
...ferenced contexts? Diana says using 'this' rather than getBaseContext, but then... most of the times A will be reused but there are situations when a new object for A will be created and then the old A leaks. So it seems that getBaseContext is the most proper choice for most cases. Then it's not cle...
Specified argument was out of the range of valid values. Parameter name: site
...Programs
open or close windows features
tick internet information services
then restart your visual studio
If using IIS Express:
Open 'Add/Remove Programs' from the old control panel and run a repair on IIS Express
Or you might go Control Panel ->> Programs ->> Programs and Features -...
IntelliJ does not show project folders
... 95% of the solution for me. I had to "Add Content Root" on that screen. Then for some reason all the folders magically appeared.
– Lavamantis
Jun 25 '15 at 20:39
2
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How to hide element using Twitter Bootstrap and show it using jQuery?
... Anyone has an idea what are the methods: show() and hide() for then?
– checklist
Apr 26 '16 at 5:11
9
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Can a constructor in Java be private?
...tions that is really an implementation detail, so you make it private, but then your remaining constructors delegate to it.
As an example of delegating constructors, the following class allows you to save a value and a type, but it only lets you do it for a subset of types, so making the general co...