CI对数据库句的操作有时很方便有时却让人为难,例如括号的问题。括号的问题来自于处理and和or的优先级关系。
有时需要or高于and。$this->db->where()和$this->db->orwhere()要如何做到呢。
第一种:自己写sql语句。可是有时候已经写好的程序要这样改动很难。
第二种:自己写where语句,有可能会遇到这样的问题。
where()和orwhere()其实是雷同的函数。
手册中有这样一段:
$this->db->where();
本函数允许你使用四种方法中的一种来设置 WHERE 子句:
说明: 传递给本函数的所有值都会被自动转义,以便生成安全的查询。
简单的 key/value 方法: $this->db->where('name', $name);// 生成: WHERE name = 'Joe'
请注意等号已经为你添加。
如果你多次调用本函数,那么这些条件会被 AND 连接起来:
$this->db->where('name', $name);$this->db->where('title', $title);
$this->db->where('status', $status);
// WHERE name = 'Joe' AND title = 'boss' AND status = 'active' 自定义 key/value 方法:
你可以在第一个参数中包含一个运算符,以便控制比较:
$this->db->where('name !=', $name);$this->db->where('id
// 生成: WHERE name != 'Joe' AND id $name, 'title' => $title, 'status' => $status);
$this->db->where($array);
// 生成: WHERE name = 'Joe' AND title = 'boss' AND status = 'active'
使用这个方法时你也可以包含运算符:
$array = array('name !=' => $name, 'id $id, 'date >' => $date);$this->db->where($array); 自定义字符串:
你可以手动的编写子句:
$where = "name='Joe' AND status='boss' OR status='active'";$this->db->where($where);
$this->db->where() 接受可选的第三个参数。如果你将它设置为 FALSE, CodeIgniter 将不会为你那些包含反勾号的字段名或表名提供保护。
$this->db->where('MATCH (field) AGAINST ("value")', NULL, FALSE);
标红的地方很重要,第4所说的:
$where = "name='Joe' AND status='boss' OR status='active'";
$this->db->where($where);
其实是行不通的。where()会给语句加上``,然后说:
"`name='Joe' AND status='boss' OR status='active'`"sql语句有错。
第三种:
改源代码:
CI论坛里有这样一段:
... ...
给like数组加上括号即可。
修改system\database\DB_active_rec.php
约第1559行
PHP
if ( count ( $this -> ar_like ) > 0 )
{
if ( count ( $this -> ar_where ) > 0 )
{
$sql .= "nAND " ;
}
$sql .= implode ( "n" , $this -> ar_like ) ;
}
改为
PHP
if ( count ( $this -> ar_like ) > 0 )
{
if ( count ( $this -> ar_where ) > 0 )
{
$sql .= "nAND (" ;
}
$sql .= implode ( "n" , $this -> ar_like ) ;
if ( count ( $this -> ar_where ) > 0 )
{
$sql .= ")" ;
}
}
希望CI开发者尽快修补or_like无法内部形成括号的BUG
这个论坛很脑残,显示回车符\n会掉一个斜杠,懂PHP的自己加上。
源自:http://codeigniter.org.cn/forums/thread-1270-1-1.html
同理,可以对where修改,但是这种只是对where语句的开始和末尾加。
对于实际的需要,几种合起来用基本情况都能解决了。不知道是不是还有更好的。呵呵,那应该就是直接修复CI源代码内部形成括号的BUG了吧

What’s still popular is the ease of use, flexibility and a strong ecosystem. 1) Ease of use and simple syntax make it the first choice for beginners. 2) Closely integrated with web development, excellent interaction with HTTP requests and database. 3) The huge ecosystem provides a wealth of tools and libraries. 4) Active community and open source nature adapts them to new needs and technology trends.

PHP and Python are both high-level programming languages that are widely used in web development, data processing and automation tasks. 1.PHP is often used to build dynamic websites and content management systems, while Python is often used to build web frameworks and data science. 2.PHP uses echo to output content, Python uses print. 3. Both support object-oriented programming, but the syntax and keywords are different. 4. PHP supports weak type conversion, while Python is more stringent. 5. PHP performance optimization includes using OPcache and asynchronous programming, while Python uses cProfile and asynchronous programming.

PHP is mainly procedural programming, but also supports object-oriented programming (OOP); Python supports a variety of paradigms, including OOP, functional and procedural programming. PHP is suitable for web development, and Python is suitable for a variety of applications such as data analysis and machine learning.

PHP originated in 1994 and was developed by RasmusLerdorf. It was originally used to track website visitors and gradually evolved into a server-side scripting language and was widely used in web development. Python was developed by Guidovan Rossum in the late 1980s and was first released in 1991. It emphasizes code readability and simplicity, and is suitable for scientific computing, data analysis and other fields.

PHP is suitable for web development and rapid prototyping, and Python is suitable for data science and machine learning. 1.PHP is used for dynamic web development, with simple syntax and suitable for rapid development. 2. Python has concise syntax, is suitable for multiple fields, and has a strong library ecosystem.

PHP remains important in the modernization process because it supports a large number of websites and applications and adapts to development needs through frameworks. 1.PHP7 improves performance and introduces new features. 2. Modern frameworks such as Laravel, Symfony and CodeIgniter simplify development and improve code quality. 3. Performance optimization and best practices further improve application efficiency.

PHPhassignificantlyimpactedwebdevelopmentandextendsbeyondit.1)ItpowersmajorplatformslikeWordPressandexcelsindatabaseinteractions.2)PHP'sadaptabilityallowsittoscaleforlargeapplicationsusingframeworkslikeLaravel.3)Beyondweb,PHPisusedincommand-linescrip

PHP type prompts to improve code quality and readability. 1) Scalar type tips: Since PHP7.0, basic data types are allowed to be specified in function parameters, such as int, float, etc. 2) Return type prompt: Ensure the consistency of the function return value type. 3) Union type prompt: Since PHP8.0, multiple types are allowed to be specified in function parameters or return values. 4) Nullable type prompt: Allows to include null values and handle functions that may return null values.


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

Dreamweaver CS6
Visual web development tools

Safe Exam Browser
Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.

SAP NetWeaver Server Adapter for Eclipse
Integrate Eclipse with SAP NetWeaver application server.

SublimeText3 Chinese version
Chinese version, very easy to use

Atom editor mac version download
The most popular open source editor