大约有 19,000 项符合查询结果（耗时：0.0412秒） [XML]
SQL Group By with an Order By
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In all versions of MySQL, simply alias the aggregate in the SELECT list, and order by the alias:
SELECT COUNT(id) AS theCount, `Tag` from `images-tags`
GROUP BY `Tag`
ORDER BY theCount DESC
LIMIT 20
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Difference between scaling horizontally and vertically for databases [closed]
...MongoDB, Google Cloud Spanner .. and a good example of vertical scaling is MySQL - Amazon RDS (The cloud version of MySQL). It provides an easy way to scale vertically by switching from small to bigger machines. This process often involves downtime.
In-Memory Data Grids such as GigaSpaces XAP, Coher...
Laravel Eloquent ORM Transactions
...t ORM is quite nice, though I'm wondering if there is an easy way to setup MySQL transactions using innoDB in the same fashion as PDO, or if I would have to extend the ORM to make this possible?
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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...
MySQL Query - Records between Today and Last 30 Days
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You can also write this in mysql -
SELECT DATE_FORMAT(create_date, '%m/%d/%Y')
FROM mytable
WHERE create_date < DATE_ADD(NOW(), INTERVAL -1 MONTH);
FIXED
share
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How to implement a tree data-structure in Java? [closed]
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Here:
public class Tree<T> {
private Node<T> root;
public Tree(T rootData) {
root = new Node<T>();
root.data = rootData;
root.children = new ArrayList<Node<T>>();
}
public static class Node<T> {
priva...
ZMQ: 基本原理 - 开源 & Github - 清泛网 - 专注C/C++及内核技术
...。
本文的目的是解释ØMQ架构的基本概念，它们是如何组合起来的，以及它们被如此设计的原因。
拓扑
拓扑是ØMQ最主要的概念，除非你知道“拓扑”代表什么，否则将与其他概念混淆更难...
ZMQ: 基本原理 - 开源 & Github - 清泛网 - 专注C/C++及内核技术
...。
本文的目的是解释ØMQ架构的基本概念，它们是如何组合起来的，以及它们被如此设计的原因。
拓扑
拓扑是ØMQ最主要的概念，除非你知道“拓扑”代表什么，否则将与其他概念混淆更难...
How to use SSH to run a local shell script on a remote machine?
...rameter, and it will execute the local script on the remote server.
plink root@MachineB -m local_script.sh
If Machine A is a Unix-based system, you can use:
ssh root@MachineB 'bash -s' < local_script.sh
You shouldn't have to copy the script to the remote server to run it.
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Best practices for SQL varchar column length [closed]
... table's varchar column. But I could not find any reference for that.
For MySQL the manual says "In most cases, ALTER TABLE makes a temporary copy of the original table". And my own tests confirm that: running an ALTER TABLE on a table with 1.2 million rows (the same as in my test with Postgres) to...