Network Tools
Technical Article
How many backslashes should be written in different situations in SQL?
A certain piece of SQL needs to parse a json string in a field. However, the Chinese characters in it are also encoded and stored in a similar format.
u6e38u620f
The SQL statement is theoretically as follows
get_json_object(extends,'$.cate')='u6e38u620f'
However, the actual system execution involves layers of compilation processes. How many backslashes should be written to select the correct result?
The experimental conclusions are as follows:
Syntax errors caused by mysql reserved keywords
When executing the original program in a new mysql environment, a syntax error is prompted. After checking, it is found that the mysql version of the environment is mysql8. The word groups has become a reserved keyword since mysql8.0.2. It is temporarily replaced by `groups`. It should still be used in the future. Be careful to avoid this kind of pitfalls.
You have an error in your SQL syntax...
Official documentation: https://dev.mysql.com/doc/refman/8.0/en/keywords.html
Mysql column conversion group_concat function
The group_concat function in MySQL can combine the specified fields of the group into one row of content, which is more suitable for column conversion.
The complete syntax is as follows:
group_concat([DISTINCT] Field to be concatenated [Order BY ASC/DESC sorting field] [Separator 'separator'])
The default delimiter is comma
Example:
select id,group_concat(distinct name) from table group by id;
It should be noted that there is a default limit on the length of the merged fields.
refer to:
The default asynchronous execution of jquery causes the problem of invalid modification of global variables
When calling a jquery ajax method, we sometimes need the method to return a value or assign a value to a global variable, but we find that the value we want is not obtained after the program is executed, for example:
Add HTTP authentication code to PHP page
// Digest HTTP Authentication // To enable, add user: "name" => "password". //$users = array(); $users = array(""=>""); // If auth is enabled: if (!empty($users)) { if (empty($_SERVER['PHP_AUTH_DIGEST'])) { header('HTTP/1.1 401 Unauthorized'); header('WWW-Authenticate: Digest realm="' . $realm . '",qop="auth",nonce="' . uniqid() . '",opaque="' . md5($realm) .
Rclone usage tutorial and detailed explanation of common command parameters
Original address: https://p3terx.com/archives/rclone-advanced-user-manual-common-command-parameters.html
Rclone is a command-line tool that supports synchronization, uploading, and downloading data between different object storage and network disks. And through some settings, very practical functions such as offline downloading and server backup can be realized. This article will explain some commonly used command parameters of Rclone.
Install Rclone
The official one-click installation script is provided:
Share several websites that create word clouds
HTTP://wuwuwu.He's happyEdo.com/app.HTML
A relatively old-fashioned foreign website tool, you need to install Microsoft Silverlight, there are templates to choose from, and the style is relatively classic;
http://thatV.promote existing loans.com/he just missed/
The blogger himself borrowed the gadget written by JavaScript plug-in;
HTTP://BJ data art.com/Web/He just missed it/
A tool that imitates foreign websites, the domestic network access speed is relatively good;
HTTP://cloud.牛coda ta.com/
Aria2 one-click installation management script
Reprinted from https://www.zrj96.com/post-420.html
**System Requirements**
CentOS 6+ / Debian 6+ / Ubuntu 14.04 +
**installation steps**
Execute the following code to download and run the script:
Solution to the abnormal damage to ppt attachment caused by outlook update
I upgraded Outlook on my office computer from 2010 to 2013, and then the ppt file I sent as an attachment could not be opened on my own computer. It said it was damaged and asked for repair, but the repair was ineffective. The file was also damaged when I saved it. The email received by others was fine. I sent it There is no problem with excel, only the pptx file is damaged. I searched online and found the solution as follows. The cause of the file damage is unknown: