select into outfile命令是mysql中一种用来导出数据的一个常用的命令,下面我来介绍select into outfile的用法,有需要的朋友可参考。
mysql管理数据当然可以很方便的导出数据,但是当数据量很大是,phpmyadmin很可能会发生执行超时,其实很容易用select into outfile解决!
SELECT...INTO OUTFILE语句的主要作用是让您可以非常快速地把一个表转储到服务器机器上。如果您想要在服务器主机之外的部分客户主机上创建结果文件,您不能使用SELECT...INTO OUTFILE。在这种情况下,您应该在客户主机上使用比如“mysql –e "SELECT ..." > file_name”的命令,来生成文件。
SELECT...INTO OUTFILE是LOAD DATA INFILE的补语;用于语句的exort_options部分的语法包括部分FIELDS和LINES子句,这些子句与LOAD DATA INFILE语句同时使用
如下:(将数据库wordpress中的wp_posts表导出到D盘)
代码如下 | 复制代码 |
select * into outfile 'd:data.txt' from wp_posts |
需要注意的是:使用select into outfile语句,必须要有执行权限,路径必须存在,否则使用当前数据库目录,
例2
代码如下 | 复制代码 |
表结构及测试数据 `id` INT(1) NOT NULL AUTO_INCREMENT PRIMARY KEY, `name` VARCHAR(10) NOT NULL, `add` VARCHAR(20) CHARACTER SET gbk NOT NULL )ENGINE=InnoDB DEFAULT CHARSET=utf8;
INSERT INTO `tab`(`name`,`add`) VALUES ('中文', '这列不会乱码'), ('汉字', '这列不会乱码');
SELECT * FROM `tab`;
+----+------+--------------+ | id | name | add | +----+------+--------------+ | 1 | 中文 | 这列不会乱码 | | 2 | 汉字 | 这列不会乱码 | +----+------+--------------+ |
代码
代码如下 | 复制代码 |
在 INTO OUTFILE 中使用变量 |
上面的代码会在C盘下生成“sql_当前时间.txt”的文件,避免INTO OUTFILE文件已存在错误
注:直接在命令行中SELECT显示无乱码,但使用 INTO OUTFILE 导出后有乱码,此时必须修改显示乱码的列的字符集

InnoDBBufferPool reduces disk I/O by caching data and indexing pages, improving database performance. Its working principle includes: 1. Data reading: Read data from BufferPool; 2. Data writing: After modifying the data, write to BufferPool and refresh it to disk regularly; 3. Cache management: Use the LRU algorithm to manage cache pages; 4. Reading mechanism: Load adjacent data pages in advance. By sizing the BufferPool and using multiple instances, database performance can be optimized.

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.

MySQL is worth learning because it is a powerful open source database management system suitable for data storage, management and analysis. 1) MySQL is a relational database that uses SQL to operate data and is suitable for structured data management. 2) The SQL language is the key to interacting with MySQL and supports CRUD operations. 3) The working principle of MySQL includes client/server architecture, storage engine and query optimizer. 4) Basic usage includes creating databases and tables, and advanced usage involves joining tables using JOIN. 5) Common errors include syntax errors and permission issues, and debugging skills include checking syntax and using EXPLAIN commands. 6) Performance optimization involves the use of indexes, optimization of SQL statements and regular maintenance of databases.

MySQL is suitable for beginners to learn database skills. 1. Install MySQL server and client tools. 2. Understand basic SQL queries, such as SELECT. 3. Master data operations: create tables, insert, update, and delete data. 4. Learn advanced skills: subquery and window functions. 5. Debugging and optimization: Check syntax, use indexes, avoid SELECT*, and use LIMIT.

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.

MySQL is an open source relational database management system that is widely used in Web development. Its key features include: 1. Supports multiple storage engines, such as InnoDB and MyISAM, suitable for different scenarios; 2. Provides master-slave replication functions to facilitate load balancing and data backup; 3. Improve query efficiency through query optimization and index use.

SQL is used to interact with MySQL database to realize data addition, deletion, modification, inspection and database design. 1) SQL performs data operations through SELECT, INSERT, UPDATE, DELETE statements; 2) Use CREATE, ALTER, DROP statements for database design and management; 3) Complex queries and data analysis are implemented through SQL to improve business decision-making efficiency.

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


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

SecLists
SecLists is the ultimate security tester's companion. It is a collection of various types of lists that are frequently used during security assessments, all in one place. SecLists helps make security testing more efficient and productive by conveniently providing all the lists a security tester might need. List types include usernames, passwords, URLs, fuzzing payloads, sensitive data patterns, web shells, and more. The tester can simply pull this repository onto a new test machine and he will have access to every type of list he needs.

WebStorm Mac version
Useful JavaScript development tools

Atom editor mac version download
The most popular open source editor

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

DVWA
Damn Vulnerable Web App (DVWA) is a PHP/MySQL web application that is very vulnerable. Its main goals are to be an aid for security professionals to test their skills and tools in a legal environment, to help web developers better understand the process of securing web applications, and to help teachers/students teach/learn in a classroom environment Web application security. The goal of DVWA is to practice some of the most common web vulnerabilities through a simple and straightforward interface, with varying degrees of difficulty. Please note that this software