大约有 7,000 项符合查询结果（耗时：0.0273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
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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...
How to find all serial devices (ttyS, ttyUSB, ..) on Linux without opening them?
... system. A trimmed down example:
# ll /sys/class/tty/ttyUSB*
lrwxrwxrwx 1 root root 0 2012-03-28 20:43 /sys/class/tty/ttyUSB0 -> ../../devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.4/2-1.4:1.0/ttyUSB0/tty/ttyUSB0/
lrwxrwxrwx 1 root root 0 2012-03-28 20:44 /sys/class/tty/ttyUSB1 -> ../../device...
css中使用变量，:root伪元素的使用 - 更多技术 - 清泛网 - 专注C/C++及内核技术
css中使用变量，:root伪元素的使用css_root前言使用css的全局变量，可以减少写很多重复代码。比如设置一个全局主题色变量，整个项目用到这个颜色的地方，都用变量设置，就很方便了。一、root伪类和css变量1 :root伪类在刚 前...
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 the ROOT application?
...fault application of a Tomcat 6 webserver to a different application than "ROOT" (inside webapps folder). What is the best way to do this?
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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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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...
Deploying my application at the root in Tomcat
I have the war file of my application. I need to deploy this at the root level. The current URL is http://localhost:8080/war_name/application_name .
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