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How do I find duplicates across multiple columns?
...simple and efficient means to locate unwanted repetition, whilst also list all affected rows and all wanted columns:
SELECT
t.*
FROM (
SELECT
s.*
, COUNT(*) OVER (PARTITION BY s.name, s.city) AS qty
FROM stuff s
) t
WHERE t.qty > 1
ORDER BY t.name, t.city
While most...
What's the difference between utf8_general_ci and utf8_unicode_ci?
...languages or characters.
On modern servers, this performance boost will be all but negligible. It was devised in a time when servers had a tiny fraction of the CPU performance of today's computers.
Benefits of utf8mb4_unicode_ci over utf8mb4_general_ci
utf8mb4_unicode_ci, which uses the Unicode r...
Regular Expression for alphanumeric and underscores
...o or more of the given characters
$ : end of string
If you don't want to allow empty strings, use + instead of *.
As others have pointed out, some regex languages have a shorthand form for [a-zA-Z0-9_]. In the .NET regex language, you can turn on ECMAScript behavior and use \w as a shorthand (y...
How to get a pixel's x,y coordinate color from an image?
...http://jsfiddle.net/thirtydot/9SEMf/869/ I used jQuery for convenience in all of this, but it is by no means required.
Note: getImageData falls under the browser's same-origin policy to prevent data leaks, meaning this technique will fail if you dirty the canvas with an image from another domain o...
UIPanGestureRecognizer - Only vertical or horizontal
I have a view that has a UIPanGestureRecognizer to drag the view vertically. So in the recognizer callback, I only update the y-coordinate to move it. The superview of this view, has a UIPanGestureRecognizer that will drag the view horizontally, just updating the x-coordinate.
...
visual c++: #include files from other projects in the same solution
...ive I've come across. Well done and thanks!
– David Hall
Apr 13 '11 at 11:50
9
There was a sugges...
“Diff” an image using ImageMagick
... as a PNG file, the second one as a PDF.
The resulting diff file displays all pixels which are different in red color. The ones which are unchanged appear white.
Short and sweet.
Note, your images need not be the same type. You can even mix JPEG, TIFF, PNG -- under one condition: the images sho...
Why escape_javascript before rendering a partial?
I'm looking at this Railscast episode and wondering why the call to escape_javascript is needed here:
4 Answers
...
How do I concatenate or merge arrays in Swift?
...ith Sequence's flatMap(_:) method
Swift provides a flatMap(_:) method for all types that conform to Sequence protocol (including Array). flatMap(_:) has the following declaration:
Returns an array containing the concatenated results of calling the given transformation with each element of this ...
call a static method inside a class?
how do i call a static method from another method inside the same class?
4 Answers
4
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