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SQL Query to concatenate column values from multiple rows in Oracle
...e oracle documentation on string aggregation techniques. A very common one is to use LISTAGG:
SELECT pid, LISTAGG(Desc, ' ') WITHIN GROUP (ORDER BY seq) AS description
FROM B GROUP BY pid;
Then join to A to pick out the pids you want.
Note: Out of the box, LISTAGG only works correctly with VARCH...
Python List vs. Array - when to use?
If you are creating a 1d array, you can implement it as a List, or else use the 'array' module in the standard library. I have always used Lists for 1d arrays.
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How can I find the number of arguments of a Python function?
...gnature class which superseded it.
Creating a Signature for the function is easy via the signature function:
from inspect import signature
def someMethod(self, arg1, kwarg1=None):
pass
sig = signature(someMethod)
Now, you can either view its parameters quickly by string it:
str(sig) # r...
Why is it not possible to extend annotations in Java?
I don't understand why there is no inheritance in Java annotations, just as Java classes. I think it would be very useful.
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How can I check if a Perl array contains a particular value?
I am trying to figure out a way of checking for the existence of a value in an array without iterating through the array.
1...
Why am I not getting a java.util.ConcurrentModificationException in this example?
...
Here's why:
As it is says in the Javadoc:
The iterators returned by this class's iterator and listIterator
methods are fail-fast: if the list is structurally modified at any
time after the iterator is created, in any way except through...
LIMIT 10..20 in SQL Server
...
The LIMIT clause is not part of standard SQL. It's supported as a vendor extension to SQL by MySQL, PostgreSQL, and SQLite.
Other brands of database may have similar features (e.g. TOP in Microsoft SQL Server), but these don't always work...
How to output something in PowerShell
... file. The script fetches a web page and checks whether the page's content is the string "OK".
7 Answers
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What's the best way to bundle static resources in a Go program? [closed]
...o help debug their applications/web services. The interface to the program is a web page which includes not only the HTML, but some JavaScript (for functionality), images and CSS (for styling). I'm planning on open-sourcing this application, so users should simply be able to run a Makefile and all t...
Parsing JSON with Unix tools
... 'https://api.github.com/users/lambda' | jq -r '.name'
You can also do this with tools that are likely already installed on your system, like Python using the json module, and so avoid any extra dependencies, while still having the benefit of a proper JSON parser. The following assume you want to ...