大约有 7,000 项符合查询结果（耗时：0.0276秒） [XML]
Count the occurrences of DISTINCT values
I am trying to find a MySQL query that will find DISTINCT values in a particular field, count the number of occurrences of that value and then order the results by the count.
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Rails 3 execute custom sql query without a model
...
How about this :
@client = TinyTds::Client.new(
:adapter => 'mysql2',
:host => 'host',
:database => 'siteconfig_development',
:username => 'username',
:password => 'password'
sql = "SELECT * FROM users"
result = @client.execute(sql)
results.each d...
绘画动画组件 · App Inventor 2 中文网
...心，否则为 球形精灵 的最高点。
Z坐标
球形精灵应如何相对于其他球形精灵和图像精灵分层，编号较高的层位于编号较低的层之前。
事件
被碰撞时(其他精灵)
事件将在两个启用的精灵（球形精灵或图像精灵）碰撞...
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...
Nginx — static file serving confusion with root & alias
...nswers to my confusions.
There is a very important difference between the root and the alias directives. This difference exists in the way the path specified in the root or the alias is processed.
In case of the root directive, full path is appended to the root including the location part, whereas...
Why do I get access denied to data folder when using adb?
... want to browse everything on your device.
You need to have a phone with root access in order to browse the data folder on an Android phone. That means either you have a developer device (ADP1 or an ION from Google I/O) or you've found a way to 'root' your phone some other way.
You need to be runn...
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.
share
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C++STL容器使用经验总结 - C/C++ - 清泛网 - 专注C/C++及内核技术
...y、stack、queue和priority_queue。
你是否关心容器中的元素是如何排序的？如果不关心，选择哈希容器.
容器中数据的布局是否需要和C兼容？如果需要兼容，就只能选择vector。(见第16条)
元素的查找速度是否是关键的考虑因素？如...
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...