Home Database Mysql Tutorial A summary of how to write commonly used SQL statements in MySQL

A summary of how to write commonly used SQL statements in MySQL

May 22, 2017 pm 02:15 PM
mysql sql statement Add index

This article mainly introduces the commonly used MySQL SQL statements for creating tables, adding fields, modifying fields, and adding indexes. It summarizes and analyzes the SQL statements involved in MySQL table creation, encoding settings, field additions, and index operations. The required Friends can refer to

. This article describes the commonly used SQL statement writing methods of creating tables, adding fields, modifying fields, and adding indexes in MySQL. Share it with everyone for your reference, the details are as follows:

Create table:

1

2

3

4

5

6

7

8

9

10

11

DROP TABLE IF EXISTS bulletin;

CREATE TABLE bulletin(

 id INT NOT NULL PRIMARY KEY AUTO_INCREMENT, # 主键

 uid INT(11) NOT NULL DEFAULT 0, # 创建者id

 context VARCHAR(600) NOT NULL DEFAULT '', # 公告详细内容(300字)

 begintime DEC(20) NOT NULL DEFAULT 0, # 公告开始时间

 endtime DEC(20) NOT NULL DEFAULT 0, # 公告结束时间

 createtime DEC(20) NOT NULL DEFAULT 0, # 创建时间

 modifytime DEC(20) NOT NULL DEFAULT 0 # 修改时间

 PRIMARY KEY (`Id`),

)DEFAULT CHARSET=UTF8 TYPE=INNODB;

Copy after login

Modify the original field name and Type:

1

ALTER TABLE bulletin CHANGE uid username VARCHAR(50) NOT NULL DEFAULT '';

Copy after login

Add new field:

1

alter table bulletin add citycode varchar(6) not null default 0; # 城市代码

Copy after login

1. Set encoding when creating database

1

create database test character set utf8;

Copy after login

2. Create table Set the encoding

1

create table test(id int primary key)DEFAULT charset=utf8;

Copy after login

3. Modify the database encoding

1

alter database test character set utf8;

Copy after login

4. Modify the table default encoding

1

alter table test character set utf8;

Copy after login

5. Modify the field encoding

1

alter table test modify col_name varchar(50) CHARACTER SET utf8;

Copy after login

Add index method

1. Add PRIMARY KEY (primary key index)

1

mysql>ALTER TABLE `table_name` ADD PRIMARY KEY ( `column` )

Copy after login

2. Add UNIQUE (unique index)

1

2

3

mysql>ALTER TABLE `table_name` ADD UNIQUE (

`column`

)

Copy after login

3 .Add INDEX (normal index)

1

mysql>ALTER TABLE `table_name` ADD INDEX index_name ( `column` )

Copy after login

4.Add FULLTEXT (full-text index)

1

2

3

mysql>ALTER TABLE `table_name` ADD FULLTEXT (

`column`

)

Copy after login

5.Add multi-column index

1

mysql>ALTER TABLE `table_name` ADD INDEX index_name ( `column1`, `column2`, `column3` )

Copy after login

[Related recommendations]

1. Mysql free video tutorial

2. Detailed explanation of how to use MySQL to generate random numbers and connect strings

3.How to improve the speed of database query for millions of items

4. 5 common database design mistakes

5. The original content of Mysql is not Detailed explanation of the sql statement that changes and adds content later

The above is the detailed content of A summary of how to write commonly used SQL statements 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

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

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

Hot Tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

Hot Topics

Java Tutorial
1662
14
PHP Tutorial
1261
29
C# Tutorial
1234
24
MySQL's Role: Databases in Web Applications 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.

Laravel Introduction Example 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.

MySQL and phpMyAdmin: Core Features and Functions 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.

Solve database connection problem: a practical case of using minii/db library 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 vs. Other Programming Languages: A Comparison 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 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 for Beginners: Getting Started with Database Management MySQL for Beginners: Getting Started with Database Management Apr 18, 2025 am 12:10 AM

The basic operations of MySQL include creating databases, tables, and using SQL to perform CRUD operations on data. 1. Create a database: CREATEDATABASEmy_first_db; 2. Create a table: CREATETABLEbooks(idINTAUTO_INCREMENTPRIMARYKEY, titleVARCHAR(100)NOTNULL, authorVARCHAR(100)NOTNULL, published_yearINT); 3. Insert data: INSERTINTObooks(title, author, published_year)VA

MySQL: Structured Data and Relational Databases MySQL: Structured Data and Relational Databases Apr 18, 2025 am 12:22 AM

MySQL efficiently manages structured data through table structure and SQL query, and implements inter-table relationships through foreign keys. 1. Define the data format and type when creating a table. 2. Use foreign keys to establish relationships between tables. 3. Improve performance through indexing and query optimization. 4. Regularly backup and monitor databases to ensure data security and performance optimization.

See all articles