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Retrieving the last record in each group - MySQL
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MySQL 8.0 now supports windowing functions, like almost all popular SQL implementations. With this standard syntax, we can write greatest-n-per-group queries:
WITH ranked_messages AS (
SELECT m.*, ROW_NUMBER() OVER (PARTITION BY name ORDER BY id DESC) AS rn
FROM messages AS m...
Storing Data in MySQL as JSON
.... And, so, I've never done it. Then I saw that FriendFeed did this and actually made their DB scale better and decreased latency. I'm curious if I should do this. And, if so, what's the right way to do it?
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Handling click events on a drawable within an EditText
...lic boolean onTouch(View v, MotionEvent event) {
final int DRAWABLE_LEFT = 0;
final int DRAWABLE_TOP = 1;
final int DRAWABLE_RIGHT = 2;
final int DRAWABLE_BOTTOM = 3;
if(event.getAction() == MotionEvent.ACTION_UP) {
if(event.getRawX() >= (editC...
In Python, how do I create a string of n characters in one line of code?
...ly, of course;-).
Other ways to "make a string of 10 characters": 'x'*10 (all the ten characters will be lowercase xs;-), ''.join(chr(ord('a')+i) for i in xrange(10)) (the first ten lowercase letters again), etc, etc;-).
sh...
Socket.IO Authentication
I am trying to use Socket.IO in Node.js, and am trying to allow the server to give an identity to each of the Socket.IO clients. As the socket code is outside the scope of the http server code, it doesn't have easy access to the request information sent, so I'm assuming it will need to be sent up d...
How to get the number of Characters in a String?
..."), utf8.RuneCountInString("世界"))
}
Phrozen adds in the comments:
Actually you can do len() over runes by just type casting.
len([]rune("世界")) will print 2. At leats in Go 1.3.
And with CL 108985 (May 2018, for Go 1.11), len([]rune(string)) is now optimized. (Fixes issue 24923)
The compile...
How to retrieve an element from a set without removing it?
...r(s)) only exceeds list(s)[0] by three characters and is otherwise dramatically superior in both time and space complexity. So, while the claim of "least code" is trivially true, it's also trivially true that this is the worst possible approach. Even manually removing and then re-adding the removed ...
How to get root access on Android emulator?
I have All Android SDK versions(from 1.5 to 2.3.3), and I tried many methods for getting root in Android emulator. I don't use any Android device and test everything on emulator(AVD).
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Possible to do a MySQL foreign key to one of two possible tables?
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What you're describing is called Polymorphic Associations. That is, the "foreign key" column contains an id value that must exist in one of a set of target tables. Typically the target tables are related in some way, such as being instances of some c...
Reload .profile in bash shell script (in unix)?
I'm new to bash shell scripting, and have come across a challenge. I know I can reload my ".profile" file by just doing:
5 ...