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The SQL OVER() clause - when and why is it useful?

I read about that clause and I don't understand why I need it. What does the function Over do? What does Partitioning By do? Why can't I make a query with writing Group By SalesOrderID ? ...
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In Java, how do I convert a byte array to a string of hex digits while keeping leading zeros? [dupli

...oach would be to check how many digits are output by Integer.toHexString() and add a leading zero to each byte if needed. Something like this: public static String toHexString(byte[] bytes) { StringBuilder hexString = new StringBuilder(); for (int i = 0; i < bytes.length; i++) { ...
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Given a class, see if instance has method (Ruby)

...don't know why everyone is suggesting you should be using instance_methods and include? when method_defined? does the job. class Test def hello; end end Test.method_defined? :hello #=> true NOTE In case you are coming to Ruby from another OO language OR you think that method_defined means ...
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How to generate and validate a software license key?

...eveloping a product (developed in C#) that'll be available for downloading and installing for free but in a very limited version. To get access to all the features the user has to pay a license fee and receive a key. That key will then be entered into the application to "unlock" the full version. ...
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How do I solve the INSTALL_FAILED_DEXOPT error?

I am developing an Android application using Android 2.2, my application APK size is 22.5 MB, and I would like to create a new build for a Samsung tablet. I got the following error: ...
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What is the difference between concurrency and parallelism?

What is the difference between concurrency and parallelism? 37 Answers 37 ...
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Is multiplication and division using shift operators in C actually faster?

Multiplication and division can be achieved using bit operators, for example 19 Answers ...
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Use rvmrc or ruby-version file to set a project gemset with RVM?

I use RVM, the Ruby Version Manager to specify a Ruby version and a set of gems for each of my Rails projects. 5 Answers ...
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How to enumerate an enum with String type?

... print($0.rawValue) } Compatibility with earlier Swift versions (3.x and 4.x) If you need to support Swift 3.x or 4.0, you may mimic the Swift 4.2 implementation by adding the following code: #if !swift(>=4.2) public protocol CaseIterable { associatedtype AllCases: Collection where AllC...
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rsync: difference between --size-only and --ignore-times

I'm trying to understand what the difference is between two options 4 Answers 4 ...