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SQL UPDATE all values in a field with appended string CONCAT not working
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convert the NULL values with empty string by wrapping it in COALESCE
"UPDATE table SET data = CONCAT(COALESCE(`data`,''), 'a')"
OR
Use CONCAT_WS instead:
"UPDATE table SET data = CONCAT_WS(',',data, 'a')"
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How do I compare version numbers in Python?
...lity but is used by setuptools (so you probably already have it installed) and is conformant to the current PEP 440; it will return a packaging.version.Version if the version is compliant and a packaging.version.LegacyVersion if not. The latter will always sort before valid versions.
Note: packagin...
Command to escape a string in bash
I need a bash command that will convert a string to something that is escaped. Here's an example:
3 Answers
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Difference between Char.IsDigit() and Char.IsNumber() in C#
What's the difference between Char.IsDigit() and Char.IsNumber() in C#?
3 Answers
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What does the constant 0.0039215689 represent?
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This multiplication by 0.0039215689f converts an integer valued color intensity in the range 0 to 255 to a real valued color intensity in the range 0 to 1.
As Ilmari Karonen points out, even if this is an optimisation it's a rather badly expressed one. It would...
How can I check if a URL exists via PHP?
...t Found') {
$exists = false;
}
else {
$exists = true;
}
From here and right below the above post, there's a curl solution:
function url_exists($url) {
return curl_init($url) !== false;
}
share
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Performance of Java matrix math libraries? [closed]
...ults are as follows.
Using multithreaded ATLAS with C/C++, Octave, Python and R, the time taken was around 4 seconds.
Using Jama with Java, the time taken was 50 seconds.
Using Colt and Parallel Colt with Java, the time taken was 150 seconds!
Using JBLAS with Java, the time taken was again aroun...
How would you compare jQuery objects?
...hare identical nodes. Here is a small code snippet. You may even want to convert this into a jquery plugin for your own uses.
jQuery(function($) {
// Two separate jQuery references
var divs = $("div");
var divs2 = $("div");
// They are equal
if (divs.length == divs2.length && d...
Array initializing in Scala
...ed here: stackoverflow.com/questions/13862568/…)
– Anderson Green
Jun 14 '13 at 22:50
add a...
str performance in python
...hon code ( python 2.6 up to 3.2 ), I discovered that the
str method to convert an object (in my case an integer) to a string is almost an order of magnitude slower than using string formatting.
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