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Subqueries vs joins
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Here's an example of how subqueries are evaluated in MySQL 6.0.
The new optimizer will convert this kind of subqueries into joins.
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How to export a Vagrant virtual machine to transfer it
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Does the "clean way" account for databases (mySQL, Wordpress) that might be inside the vm? How can that be synced over to the other pc?
– kevllar
Feb 17 '16 at 4:33
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Is storing a delimited list in a database column really that bad?
...ient table-scan. May have to resort to regular expressions, for example in MySQL:
idlist REGEXP '[[:<:]]2[[:>:]]'*
Hard to count elements in the list, or do other aggregate queries.
Hard to join the values to the lookup table they reference.
Hard to fetch the list in sorted order.
To solve th...
how to change default python version?
...meworks/Python.framework/Versions/3.2/bin/
$ ls -l
total 384
lrwxr-xr-x 1 root admin 8 Apr 28 15:51 2to3@ -> 2to3-3.2
-rwxrwxr-x 1 root admin 140 Feb 20 11:14 2to3-3.2*
lrwxr-xr-x 1 root admin 7 Apr 28 15:51 idle3@ -> idle3.2
-rwxrwxr-x 1 root admin 138 Feb 20 11:14 idl...
What is sharding and why is it important?
...cross multiple logical or physical nodes (in the case of my understanding (mySQL) multiple databases, most likely housed on different logical hardware). Horizontal partitioning is a less specific term, of which "Sharding" is a subset. Again using mySQL as an example, a mySQL partition is handled by...
How to check if running as root in a bash script
I'm writing a script that requires root level permissions, and I want to make it so that if the script is not run as root, it simply echoes "Please run as root." and exits.
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基于PECL OAuth打造微博应用 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...last_response = null;
return $instance;
}
?>
先看看搜狐是如何发送文本加图片消息的：
<?php
$text = 'hello, world.';
$image = 'http://www.foo.com/bar.gif';
$oauth = OAuth(
'YOUR_CONSUMER_KEY',
'YOUR_CONSUMER_SECRET',
OAUTH_SIG_METHOD_HMACSHA1,
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In JPA 2, using a CriteriaQuery, how to count results
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Mind you that the qb.count is done over the Root<MyEntity> of your query (Root<MyEntity> myEntity = cq.from(MyEntity.class)) and this is often already in your normal select code and when you forget you end up with a join to self.
– gke...
Select something that has more/less than x character
...nks.
Here's the link to the MSDN
For oracle/plsql you can use Length(), mysql also uses Length.
Here is the Oracle documentation:
http://www.techonthenet.com/oracle/functions/length.php
And here is the mySQL Documentation of Length(string):
http://dev.mysql.com/doc/refman/5.1/en/string-functi...
Determine if running on a rooted device
...has a certain piece of functionality that will only work on a device where root is available. Rather than having this feature fail when it is used (and then show an appropriate error message to the user), I'd prefer an ability to silently check if root is available first, and if not,hide the respect...