由于业务需求在产品表中增加了几个排序字段。但是默认排序字段(sort)的值是0
然后用了几天以后有些产品的字段值运营已经在后台设置了sort值,但是剩下的那些sort值还是0的产品当检索的时候是按怎样的逻辑进行排序的?
PS:auto_id
是主键 id
是php随机生成的产品唯一号
<code>SELECT id,title,auto_id,web_sort FROM `route` WHERE class = 2 AND `status` = 1 AND product_library = 0 ORDER BY web_sort DESC; </code>
回复内容:
由于业务需求在产品表中增加了几个排序字段。但是默认排序字段(sort)的值是0
然后用了几天以后有些产品的字段值运营已经在后台设置了sort值,但是剩下的那些sort值还是0的产品当检索的时候是按怎样的逻辑进行排序的?
PS:auto_id
是主键 id
是php随机生成的产品唯一号
<code>SELECT id,title,auto_id,web_sort FROM `route` WHERE class = 2 AND `status` = 1 AND product_library = 0 ORDER BY web_sort DESC; </code>
按理说应该是根据主键的顺序,因为这个表中数据的物理顺序,查询一般都是按顺序在遍历表的。但是很奇怪你的查询结果为什么是乱的,我本地试了一下都是主键顺序。
如果你真的需要一个特殊的第二排序要求,在查询语句中可以自己加上第二排序的规则。例如以auto_id的ASC为序:
<code>SELECT id,title,auto_id,web_sort FROM `route` WHERE class = 2 AND `status` = 1 AND product_library = 0 ORDER BY web_sort DESC, auto_id ASC; </code>

TomodifydatainaPHPsession,startthesessionwithsession_start(),thenuse$_SESSIONtoset,modify,orremovevariables.1)Startthesession.2)Setormodifysessionvariablesusing$_SESSION.3)Removevariableswithunset().4)Clearallvariableswithsession_unset().5)Destroythe

Arrays can be stored in PHP sessions. 1. Start the session and use session_start(). 2. Create an array and store it in $_SESSION. 3. Retrieve the array through $_SESSION. 4. Optimize session data to improve performance.

PHP session garbage collection is triggered through a probability mechanism to clean up expired session data. 1) Set the trigger probability and session life cycle in the configuration file; 2) You can use cron tasks to optimize high-load applications; 3) You need to balance the garbage collection frequency and performance to avoid data loss.

Tracking user session activities in PHP is implemented through session management. 1) Use session_start() to start the session. 2) Store and access data through the $_SESSION array. 3) Call session_destroy() to end the session. Session tracking is used for user behavior analysis, security monitoring, and performance optimization.

Using databases to store PHP session data can improve performance and scalability. 1) Configure MySQL to store session data: Set up the session processor in php.ini or PHP code. 2) Implement custom session processor: define open, close, read, write and other functions to interact with the database. 3) Optimization and best practices: Use indexing, caching, data compression and distributed storage to improve performance.

PHPsessionstrackuserdataacrossmultiplepagerequestsusingauniqueIDstoredinacookie.Here'showtomanagethemeffectively:1)Startasessionwithsession_start()andstoredatain$_SESSION.2)RegeneratethesessionIDafterloginwithsession_regenerate_id(true)topreventsessi

In PHP, iterating through session data can be achieved through the following steps: 1. Start the session using session_start(). 2. Iterate through foreach loop through all key-value pairs in the $_SESSION array. 3. When processing complex data structures, use is_array() or is_object() functions and use print_r() to output detailed information. 4. When optimizing traversal, paging can be used to avoid processing large amounts of data at one time. This will help you manage and use PHP session data more efficiently in your actual project.

The session realizes user authentication through the server-side state management mechanism. 1) Session creation and generation of unique IDs, 2) IDs are passed through cookies, 3) Server stores and accesses session data through IDs, 4) User authentication and status management are realized, improving application security and user experience.


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

Atom editor mac version download
The most popular open source editor

Dreamweaver CS6
Visual web development tools

EditPlus Chinese cracked version
Small size, syntax highlighting, does not support code prompt function

Dreamweaver Mac version
Visual web development tools

SublimeText3 English version
Recommended: Win version, supports code prompts!
