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Select rows which are not present in other table
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There are basically 4 techniques for this task, all of them standard SQL.
NOT EXISTS
Often fastest in Postgres.
SELECT ip
FROM login_log l
WHERE NOT EXISTS (
SELECT -- SELECT list mostly irrelevant; can just be empty in Postgres
FROM ip_location
WHERE ip = l.ip
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Is String.Format as efficient as StringBuilder
...would run more quickly using .Append(). But it's a guess, try benchmarking and/or profiling the two to get a proper comparison.
This chap, Jerry Dixon, did some benchmarking:
http://jdixon.dotnetdevelopersjournal.com/string_concatenation_stringbuilder_and_stringformat.htm
Updated:
Sadly the ...
Returning 'IList' vs 'ICollection' vs 'Collection'
...bout which collection type that I should return from my public API methods and properties.
6 Answers
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What is the purpose of the -nodes argument in openssl?
...te key in a PKCS#12 file.
To encrypt the private key, you can omit -nodes and your key will be encrypted with 3DES-CBC. To encrypt the key, OpenSSL prompts you for a password and it uses that password to generate an encryption key using the key-derivation function EVP_BytesToKey.
Depending on you...
Is MonoTouch now banned on the iPhone? [closed]
...or compatibility layer or tool are prohibited
Kind of a bummer, MonoTouch and the Flash CS5 -> iPhone converter are very cool.
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How to compare dates in Java? [duplicate]
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Date has before and after methods and can be compared to each other as follows:
if(todayDate.after(historyDate) && todayDate.before(futureDate)) {
// In between
}
For an inclusive comparison:
if(!historyDate.after(todayDate) ...
Is there a way to zoom the Visual Studio text editor with a keyboard shortcut?
Yesterday I found myself needing to zoom my Visual Studio text editor and was without a mouse (don't ask). Typically I do this by holding down CTRL and scrolling the mouse wheel. I also couldn't figure out how to tab into the area where you can specify your zoom level in the lower left hand corner...
Why fragments, and when to use fragments instead of activities?
In Android API 11+, Google has released a new class called Fragment .
11 Answers
11
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Vim: Move cursor to its last position
...r to its previous position (while in normal mode)? Something to cycle back and forth in the list of previous cursor positions would be ideal. But also just to switch to the last location would suffice (something like cd - in bash with directories).
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How to delete a word and go into insert mode in Vim?
...mal mode I can hit Ctrl + E which deletes the rest of the current word and goes to insert mode.
5 Answers
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