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Why is SSE scalar sqrt(x) slower than rsqrt(x) * x?
...th on an Intel Core Duo, and while looking at various approaches to square root I've noticed something odd: using the SSE scalar operations, it is faster to take a reciprocal square root and multiply it to get the sqrt, than it is to use the native sqrt opcode!
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How to change MySQL column definition?
I have a mySQL table called test:
3 Answers
3
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Is there a good reason I see VARCHAR(255) used so often (as opposed to another length)?
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@CharlesBretana: By "fake UTF-8" I mean MySQL's "utf8" encoding, which as I mentioned reserves (and is limited to) 3 bytes per character. This isn't a very good version of UTF-8; if you want decent UTF-8 in MySQL, you have to use its "utf8mb4" encoding. But peopl...
What's the difference between HEAD^ and HEAD~ in Git?
... / ],
F => [ qw/ I J / ],
);
sub postorder {
my($root,$hash) = @_;
my @parents = @{ $parents{$root} || [] };
postorder($_, $hash) for @parents;
return if $sha1{$root};
@parents = map "-p $sha1{$_}", @parents;
chomp($sha1{$root} = `git commit-tree @parents -m "$roo...
MySQL/SQL: Group by date only on a Datetime column
...son. I would expect it to fail anywhere else as well. Can you confirm that MySQL actually handles this query?
– Tomalak
Dec 14 '08 at 15:56
1
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MySQL convert date string to Unix timestamp
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You will certainly have to use both STR_TO_DATE to convert your date to a MySQL standard date format, and UNIX_TIMESTAMP to get the timestamp from it.
Given the format of your date, something like
UNIX_TIMESTAMP(STR_TO_DATE(Sales.SalesDate, '%M %e %Y %h:%i%p'))
Will gives you a valid timestam...
How to convert timestamp to datetime in MySQL?
How to convert 1300464000 to 2011-03-18 16:00:00 in MySQL?
5 Answers
5
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How to count total number of watches on a page?
...ange body to html or wherever you put your ng-app)
(function () {
var root = angular.element(document.getElementsByTagName('body'));
var watchers = [];
var f = function (element) {
angular.forEach(['$scope', '$isolateScope'], function (scopeProperty) {
if (element...
Where can I download english dictionary database in a text format? [closed]
... replace the deprecated syntax before running it against a 5.0+ version of MySQL
– Serguei Fedorov
Aug 16 '18 at 2:10
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In MySQL queries, why use join instead of where?
... Performance Perspective:
Where supported (Oracle 9i+, PostgreSQL 7.2+, MySQL 3.23+, SQL Server 2000+), there is no performance benefit to using either syntax over the other. The optimizer sees them as the same query. But more complex queries can benefit from using ANSI-92 syntax:
Ability to ...