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In SQL, what's the difference between count(column) and count(*)?
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count(*) counts NULLs and count(column) does not
[edit] added this code so that people can run it
create table #bla(id int,id2 int)
insert #bla values(null,null)
insert #bla values(1,null)
insert #bla values(null,1)
insert #bla values(1,null)
in...
What is a StackOverflowError?
What is a StackOverflowError , what causes it, and how should I deal with them?
15 Answers
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Writing a dict to txt file and reading it back?
...mes not recommended. The problem is that eval() will evaluate any string, and if someone tricked you into running a really tricky string, something bad might happen. In this case, you are just running eval() on your own file, so it should be okay.
But because eval() is useful, someone made an alt...
Explanation of JSONB introduced by PostgreSQL
PostgreSQL just introduced JSONB and it's already trending on hacker news . It would be great if someone could explain how it's different from Hstore and JSON previously present in PostgreSQL. What are its advantages and limitations and when should someone consider using it?
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Scrollview vertical and horizontal in android
I'm really tired looking for a solution for vertical and horizontal Scrollview.
11 Answers
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What is array to pointer decay?
...mbers = 0x5a5aff23. More importantly the term decay signifies loss of type and dimension; numbers decay into int* by losing the dimension information (count 5) and the type is not int [5] any more. Look here for cases where the decay doesn't happen.
If you're passing an array by value, what you're ...
A proper wrapper for console.log with correct line number?
I'm now developing an application, and place a global isDebug switch. I would like to wrap console.log for more convenient usage.
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How to recursively download a folder via FTP on Linux [closed]
I'm trying to ftp a folder using the command line ftp client, but so far I've only been able to use 'get' to get individual files.
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How to measure time taken between lines of code in python?
...f you want to measure CPU time, can use time.process_time() for Python 3.3 and above:
import time
start = time.process_time()
# your code here
print(time.process_time() - start)
First call turns the timer on, and second call tells you how many seconds have elapsed.
There is also a function t...
When exactly are onSaveInstanceState() and onRestoreInstanceState() called?
...igure (from the official doc ) describes the well-known lifecycle of an Android activity:
5 Answers
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