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What's faster, SELECT DISTINCT or GROUP BY in MySQL?
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They are essentially equivalent to each other (in fact this is how some databases implement DISTINCT under the hood).
If one of them is faster, it's going to be DISTINCT. This is because, although the two are the same, a query optimizer wo...
If i synchronized two methods on the same class, can they run simultaneously?
... a add on to this question. Suppose both method are static now methodA is called using Class while methodB is called using object like A.methodA() in t1 and obj.methodB() in t2. What will happen now, will they block????
– amod
Mar 21 '13 at 12:16
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Is there a “previous sibling” selector?
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I found a way to style all previous siblings (opposite of ~) that may work depending on what you need.
Let's say you have a list of links and when hovering on one, all the previous ones should turn red. You can do it like this:
/* default lin...
Use 'import module' or 'from module import'?
...eadability: Any name conflicts will show themselves in (unit) testing. But all the names you use from the imported module will be bare, with nary a hint were they come from. I absolutely loathe "import *".
– Jürgen A. Erhard
Dec 26 '09 at 19:59
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Dealing with “java.lang.OutOfMemoryError: PermGen space” error
...rvice.
If you get an error the specified service does not exist as an installed service you should run:
tomcat6w //ES//servicename
where servicename is the name of the server as viewed in services.msc
Source: orx's comment on Eric's Agile Answers.
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Fetch the row which has the Max value for a column
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This will retrieve all rows for which the my_date column value is equal to the maximum value of my_date for that userid. This may retrieve multiple rows for the userid where the maximum date is on multiple rows.
select userid,
my_date,
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How to show git log history for a sub directory of a git repo?
...ne -- src/nvfs
d6f6b3b Changes for Mac OS X
803fcc3 Initial Commit
# Show all changes (one additional commit besides in src/nvfs).
$ git log --oneline
d6f6b3b Changes for Mac OS X
96cbb79 gitignore
803fcc3 Initial Commit
s...
How do I enable the column selection mode in Eclipse?
News wrote that Eclipse 3.5 finally supports column selection.
Unfortunately I don't know HOW to enable it. I tried pressing the ALT-key like I am used to in Visual Studio and all other Microsoft products but that had no effect.
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How to list the size of each file and directory and sort by descending size in Bash?
... @ErikTrautman to list the files also you need to add -a and use --all instead of --max-depth=1 like so du -a -h --all | sort -h
– Franco
Jun 14 '14 at 1:40
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How to remove application from app listings on Android Developer Console
...et you cannot delete it. (Each package name is unique and Google remembers all package names anyway so you could use this a reminder)
The "Delete" button only works for unpublished version of your app. Once you published your app or a particular version of it, you cannot delete it from the Market. H...