大约有 40,000 项符合查询结果（耗时：0.0471秒） [XML]
John Carmack's Unusual Fast Inverse Square Root (Quake III)
... function in the Quake III source code which calculates the inverse square root of a float, 4x faster than regular (float)(1.0/sqrt(x)) , including a strange 0x5f3759df constant. See the code below. Can someone explain line by line what exactly is going on here and why this works so much faster t...
PHP mkdir: Permission denied problem
..., all you need it's to obtain correct path. I did it this way:
<?php
$root = $_SERVER["DOCUMENT_ROOT"];
$dir = $root . '/somefolder/';
if( !file_exists($dir) ) {
mkdir($dir, 0755, true);
}
?>
share
|
...
MySQL Multiple Joins in one query?
....new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f8974328%2fmysql-multiple-joins-in-one-query%23new-answer', 'question_page');
}
);
Post as a guest
...
Finding duplicate values in a SQL table
...QL Server 2017) still requires all non-aggregated columns in the GROUP BY.
MySQL is unpredictable and you need sql_mode=only_full_group_by:
GROUP BY lname ORDER BY showing wrong results;
Which is the least expensive aggregate function in the absence of ANY() (see comments in accepted answer).
Ora...
Common MySQL fields and their appropriate data types
I am setting up a very small MySQL database that stores, first name, last name, email and phone number and am struggling to find the 'perfect' datatype for each field. I know there is no such thing as a perfect answer, but there must be some sort of common convention for commonly used fields such as...
cpuid汇编指令 - C/C++ - 清泛网 - 专注C/C++及内核技术
...一组返回的是基本信息，另一组返回的是扩展信息。
1、如何判断CPU是否支持CPUID指令
前面说过，大概是从80486开始才有的cpuid这个指令，是不是所有的80486家族CPU都有这个指令我也不是很清楚，但在EFLAGS中的bit 21可以识别CPU...
INSERT with SELECT
... lets you put whatever you inserted into another table also. I don't think MySQL has an equivalent. You might create a temporary table, select into that table, then populate courses from that table, then use the temp table for whatever else you needed.
– Andrew
...
How can I brew link a specific version?
...Usage: brew switch <formula> <version>
Example:
brew switch mysql 5.5.29
You can find the versions installed on your system with info.
brew info mysql
And to see the available versions to install, you can provide a dud version number, as brew will helpfully respond with the avail...
How to print SQL statement in codeigniter model
...
Fatal error: Call to undefined method CI_DB_mysql_driver::get_compiled_select()
– itskawsar
Sep 25 '13 at 8:53
add a comment
...
PHP_SELF vs PATH_INFO vs SCRIPT_NAME vs REQUEST_URI
... The filename of the currently executing script, relative to the document root. For instance, $_SERVER['PHP_SELF'] in a script at the address http://example.com/test.php/foo.bar would be /test.php/foo.bar. The __FILE__ constant contains the full path and filename of the current (i.e. included) file...