Usage analysis of regular expression replacement using replace and regexp in MySQL-Mysql Tutorial-php.cn

Home

Database

Mysql Tutorial

Usage analysis of regular expression replacement using replace and regexp in MySQL

黄舟

Mar 15, 2017 pm 05:17 PM

This article mainly introduces the usage of regular expression using replace and regexp in MySQL, and analyzes the usage techniques and use of replace and regexp regular expression in combination with specific examples. For related notes, friends in need can refer to the following

This article describes the use of replace and regexp for regular expression replacement in MySQL. Share it with everyone for your reference, the details are as follows:

Today a friend asked me if I could modify all the formats similar to "./uploads/110100_cityHotel_Beijing Fu Luxury Hotel.jpg" found in the database. It is in the format of "./uploads/110100cityHotelBeijing Fu Luxury Hotel.jpg". I have never processed data in this way, but I know that mysql can use replace, and regular expressions can also do it.

How to do it?

We only need such a statement,

The code is as follows:

update master_data.md_employee set name=replace(name,"_",&#39;&#39;) where id = 825;

Copy after login

-- Note replace(field name, "Character to be replaced", "Character to be replaced"), this is it.

In Mysql, replace and regexp mainly realize data replacement through sql statements.

Let’s first talk about the specific usage of replace.

mysql replace usage

1.replace into

##The code is as follows:

replace into table (id,name) values(&#39;1′,&#39;aa&#39;),(&#39;2′,&#39;bb&#39;)

Copy after login

The function of this statement is to insert two records into the table. If the primary key id is 1 or 2 and does not exist

is equivalent to

The code is as follows:

insert into table (id,name) values(&#39;1′,&#39;aa&#39;),(&#39;2′,&#39;bb&#39;)

Copy after login

If the same value exists, it will not

Insert data
##2.

replace(

object,search,replace)<a href="http://www.php.cn/wiki/60.html" target="_blank"></a>Replace all occurrences of search in object Replace with replace

The code is as follows:

select replace(&#39;www.jb51.net&#39;,&#39;w&#39;,&#39;Ww&#39;)

Copy after login

Example: Replace aa in the name field in the table with bb

The code is as follows:

update table set name=replace(name,&#39;aa&#39;,&#39;bb&#39;)

Copy after login

Other

types of pattern matching provided by MySQL use extended regular expressions.

When you test for matches on such patterns, use the REGEXP and NOT REGEXP

operators (or RLIKE and NOT RLIKE, which are synonyms). Some characters that extend regular expressions are:

· ‘.’ matches any single character.

Character Class "[...]" matches any character within square brackets. For example, "[abc]" matches "a", "b", or "c". To name a range of characters, use a "-". "[a-z]" matches any letter, while "[0-9]" matches any number.

· " * " matches zero or more characters preceding it. For example, "x*" matches any number of "x" characters, "[0-9]*" matches any number of digits, and ".*" matches any number of any characters.

The pattern matches if the REGEXP pattern matches anywhere in the value being tested (this is different from LIKE pattern matching, which only matches the entire value).

To position a pattern so that it must match the beginning or end of the value being tested, use "^" at the beginning of the pattern or "$" at the end of the pattern.

To illustrate how extended regular expressions work, let’s rewrite the LIKE

query shown above using REGEXP

: 1. In order to find out what starts with “d For names starting with ", use "^" to match the beginning of the name:

The code is as follows:

SELECT * FROM master_data.md_employee WHERE name REGEXP &#39;^d&#39;;

Copy after login

Such a result set is not case-sensitive, if you want to force REGEXP The comparison is case-sensitive, and the BINARY keyword is used to make one of the

strings

into a binary string. This query only matches the first letter of the name, lowercase 'd'.
The code is as follows:

SELECT * FROM master_data.md_employee WHERE name REGEXP BINARY&#39;^d&#39;;

Copy after login

To find names ending with "love", use "$" to match the end of the name:

The code is as follows :

SELECT id,name FROM master_data.md_employee WHERE name REGEXP &#39;love$&#39;;

Copy after login

To find names that contain a "w", use the following query:

The code is as follows:

SELECT id,name FROM master_data.md_employee WHERE name REGEXP &#39;w&#39;;

Copy after login

Since if a regular expression appears in Anywhere in the value that the pattern matches, you don't have to put a wildcard on either side of the pattern in the previous query to make it match the entire value, just like you would if you used an SQL pattern.

To find names that contain exactly 5 characters, use "^" and "$" to match the beginning and end of the name, and 5 "." instances in between:

code show as below:

SELECT id,name FROM master_data.md_employee WHERE name REGEXP &#39;^.....$&#39;;

Copy after login

你也可以使用“{n}”“重复n次”操作符重写前面的查询：

代码如下:

SELECT id,name FROM master_data.md_employee WHERE name REGEXP &#39;^.{5}$&#39;;

Copy after login

这些知识一些简单的mysql的replace和regexp的用法，对于深入的学习，我们会在之后的文章会将具体的例子以及用法写出

The above is the detailed content of Usage analysis of regular expression replacement using replace and regexp in MySQL. For more information, please follow other related articles on the PHP Chinese website!

Statement of this Website

The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

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

How to fix KB5055523 fails to install in Windows 11?

3 weeks ago By DDD

How to fix KB5055518 fails to install in Windows 10?

3 weeks ago By DDD

Roblox: Dead Rails - How To Tame Wolves

4 weeks ago By DDD

Strength Levels for Every Enemy & Monster in R.E.P.O.

4 weeks ago By 尊渡假赌尊渡假赌尊渡假赌

Roblox: Grow A Garden - Complete Mutation Guide

2 weeks ago By DDD

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

Java Tutorial

1659

CakePHP Tutorial

1415

Laravel Tutorial

1309

PHP Tutorial

1257

C# Tutorial

1231

Related knowledge

MySQL's Role: Databases in Web Applications Apr 17, 2025 am 12:23 AM

The main role of MySQL in web applications is to store and manage data. 1.MySQL efficiently processes user information, product catalogs, transaction records and other data. 2. Through SQL query, developers can extract information from the database to generate dynamic content. 3.MySQL works based on the client-server model to ensure acceptable query speed.

How to start mysql by docker Apr 15, 2025 pm 12:09 PM

The process of starting MySQL in Docker consists of the following steps: Pull the MySQL image to create and start the container, set the root user password, and map the port verification connection Create the database and the user grants all permissions to the database

Laravel Introduction Example Apr 18, 2025 pm 12:45 PM

Laravel is a PHP framework for easy building of web applications. It provides a range of powerful features including: Installation: Install the Laravel CLI globally with Composer and create applications in the project directory. Routing: Define the relationship between the URL and the handler in routes/web.php. View: Create a view in resources/views to render the application's interface. Database Integration: Provides out-of-the-box integration with databases such as MySQL and uses migration to create and modify tables. Model and Controller: The model represents the database entity and the controller processes HTTP requests.

Solve database connection problem: a practical case of using minii/db library Apr 18, 2025 am 07:09 AM

I encountered a tricky problem when developing a small application: the need to quickly integrate a lightweight database operation library. After trying multiple libraries, I found that they either have too much functionality or are not very compatible. Eventually, I found minii/db, a simplified version based on Yii2 that solved my problem perfectly.

MySQL and phpMyAdmin: Core Features and Functions Apr 22, 2025 am 12:12 AM

MySQL and phpMyAdmin are powerful database management tools. 1) MySQL is used to create databases and tables, and to execute DML and SQL queries. 2) phpMyAdmin provides an intuitive interface for database management, table structure management, data operations and user permission management.

MySQL vs. Other Programming Languages: A Comparison Apr 19, 2025 am 12:22 AM

Compared with other programming languages, MySQL is mainly used to store and manage data, while other languages such as Python, Java, and C are used for logical processing and application development. MySQL is known for its high performance, scalability and cross-platform support, suitable for data management needs, while other languages have advantages in their respective fields such as data analytics, enterprise applications, and system programming.

Laravel framework installation method Apr 18, 2025 pm 12:54 PM

Article summary: This article provides detailed step-by-step instructions to guide readers on how to easily install the Laravel framework. Laravel is a powerful PHP framework that speeds up the development process of web applications. This tutorial covers the installation process from system requirements to configuring databases and setting up routing. By following these steps, readers can quickly and efficiently lay a solid foundation for their Laravel project.

MySQL vs. Other Databases: Comparing the Options Apr 15, 2025 am 12:08 AM

MySQL is suitable for web applications and content management systems and is popular for its open source, high performance and ease of use. 1) Compared with PostgreSQL, MySQL performs better in simple queries and high concurrent read operations. 2) Compared with Oracle, MySQL is more popular among small and medium-sized enterprises because of its open source and low cost. 3) Compared with Microsoft SQL Server, MySQL is more suitable for cross-platform applications. 4) Unlike MongoDB, MySQL is more suitable for structured data and transaction processing.

See all articles