PHP中使用MySQL按照多字段排序及问题解决
因为在做一个项目需要筛选掉一部分产品列表中的产品,使其在列表显示时排在最后,但是所有产品都要按照更新时间排序。
研究了一下系统的数据库结构后,决定将要排除到后面的产品加为粗体,这样在数据库中的“ifbold”就会被标记为1,而其他产品就默认标记为0,然后就打算使用MySQL在Order By时进行多字段排序。
Orderby的多条件分割一般使用英文逗号分割,所以我测试的SQL如下:
select * from {P}_product_con where $scl order by 'ifbold' asc,$myord desc limit $pagelimit"
但是运行后没有将”ifbold“正序,但是单纯正序”ifbold“却正常,调试了N久,无意中在phpMyAdmin中运行却发现正常,仔细比对后发现问题原来是来自于”ifblod“的引号上。改为下列语句就正常了:
select * from {P}_product_con where $scl order by `ifbold` asc,$myord desc limit $pagelimit
所以以后大家再程序中写SQL语句时也要注意引号的问题哦!
本文来源:http://blog.yourtion.com

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

AI Hentai Generator
Generate AI Hentai for free.

Hot Article

Hot Tools

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

Hot Topics



The future of PHP will be achieved by adapting to new technology trends and introducing innovative features: 1) Adapting to cloud computing, containerization and microservice architectures, supporting Docker and Kubernetes; 2) introducing JIT compilers and enumeration types to improve performance and data processing efficiency; 3) Continuously optimize performance and promote best practices.

PHP and Python each have their own advantages, and the choice should be based on project requirements. 1.PHP is suitable for web development, with simple syntax and high execution efficiency. 2. Python is suitable for data science and machine learning, with concise syntax and rich libraries.

MySQL is an open source relational database management system. 1) Create database and tables: Use the CREATEDATABASE and CREATETABLE commands. 2) Basic operations: INSERT, UPDATE, DELETE and SELECT. 3) Advanced operations: JOIN, subquery and transaction processing. 4) Debugging skills: Check syntax, data type and permissions. 5) Optimization suggestions: Use indexes, avoid SELECT* and use transactions.

You can open phpMyAdmin through the following steps: 1. Log in to the website control panel; 2. Find and click the phpMyAdmin icon; 3. Enter MySQL credentials; 4. Click "Login".

MySQL and SQL are essential skills for developers. 1.MySQL is an open source relational database management system, and SQL is the standard language used to manage and operate databases. 2.MySQL supports multiple storage engines through efficient data storage and retrieval functions, and SQL completes complex data operations through simple statements. 3. Examples of usage include basic queries and advanced queries, such as filtering and sorting by condition. 4. Common errors include syntax errors and performance issues, which can be optimized by checking SQL statements and using EXPLAIN commands. 5. Performance optimization techniques include using indexes, avoiding full table scanning, optimizing JOIN operations and improving code readability.

PHP is not dying, but constantly adapting and evolving. 1) PHP has undergone multiple version iterations since 1994 to adapt to new technology trends. 2) It is currently widely used in e-commerce, content management systems and other fields. 3) PHP8 introduces JIT compiler and other functions to improve performance and modernization. 4) Use OPcache and follow PSR-12 standards to optimize performance and code quality.

Redis uses a single threaded architecture to provide high performance, simplicity, and consistency. It utilizes I/O multiplexing, event loops, non-blocking I/O, and shared memory to improve concurrency, but with limitations of concurrency limitations, single point of failure, and unsuitable for write-intensive workloads.

How to connect to MySQL using phpMyAdmin? The URL to access phpMyAdmin is usually http://localhost/phpmyadmin or http://[your server IP address]/phpmyadmin. Enter your MySQL username and password. Select the database you want to connect to. Click the "Connection" button to establish a connection.
