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Postgresql aggregate array
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What I understand you can do something like this:
SELECT p.p_name,
STRING_AGG(Grade.Mark, ',' ORDER BY Grade.Mark) As marks
FROM Student
LEFT JOIN Grade ON Grade.Student_id = Student.Id
GROUP BY Student.Name;
EDIT
I am not sure. B...
Why are there two build.gradle files in an Android Studio project?
After having imported an Eclipse project into Android Studio, I see two build.gradle files:
2 Answers
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What does “all” stand for in a makefile?
...rning Makefiles but for me it is still unclear for what the target "all" stands for and what it does.
4 Answers
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Best way to check if a Data Table has a null value in it
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Try comparing the value of the column to the DBNull.Value value to filter and manage null values in whatever way you see fit.
foreach(DataRow row in table.Rows)
{
object value = row["ColumnName"];
if (value == DBNull.Value)
// do something
else
// do something else
}
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Regular expression for a string containing one word but not another
I'm setting up some goals in Google Analytics and could use a little regex help.
4 Answers
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Read and overwrite a file in Python
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If you don't want to close and reopen the file, to avoid race conditions, you could truncate it:
f = open(filename, 'r+')
text = f.read()
text = re.sub('foobar', 'bar', text)
f.seek(0)
f.write(text)
f.truncate()
f.close()
The functionality will likely...
Find and copy files
...*.xml' -exec cp "{}" /home/shantanu/tosend \;
Please, note: the find command use {} as placeholder for matched file.
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Is there any way to view the currently mapped keys in Vim?
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You can do that with the :map command. There are also other variants.
:nmap for normal mode mappings
:vmap for visual mode mappings
:imap for insert mode mappings
The above list is not complete. Typing :help map in Vim will give you more info.
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How to format all Java files in an Eclipse project at one time?
I have an old Eclipse project and the code is not well formatted. I'd like to format all the .java files according to the settings in Eclipse. I don't want to edit every individual file with Ctrl + Shift + F . Is there a way to format all my files? Perhaps an Eclipse plugin?
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Hide Console Window in C# Console Application
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Console window flashes and goes back. How do i keep the application running with no window at all?
– SOF User
Oct 4 '10 at 8:29
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