SQL 教程

SQL主页 SQL简介 SQL语法 SQL选择 SQL选择 Distinct SQL位置 SQL运算符 SQL排序依据 SQL插入 SQL空值 SQL更新 SQL删除 SQL选择 Top SQL最小和最大 SQL计数 SQL喜爱 SQL通配符 SQL输入 SQL之间 SQL别名 SQL连接 SQL输入ner Join SQL左联接 SQL右连接 SQL完全联接 SQL自连接 SQL联盟 SQL分组依据 SQL具有 SQL存在 SQL全部 SQL选择 Into SQL插入 Select SQL案例 SQL空函数 SQL存储过程 SQL注释

SQL 数据库

SQL创建数据库 SQL Drop DB SQL备份数据库 SQL创建表 SQL删除表 SQL变更表 SQL约束 SQL不为空 SQL唯一 SQL主键 SQL外键 SQL检查 SQL默认值 SQL输入dex SQL自动增量 SQL日期 SQL视图 SQL输入jection SQL托管

SQL 参考

SQL关键字 MySQL函数 SQL Server函数 MS Access功能 SQL运算符 SQL数据类型 SQL快速参考

SQL 示例

SQL 示例 SQL测验 SQL 练习 SQL证书

SQL Tutorial

SQL is a standard language for storing, manipulating and retrieving data in databases.

Our SQL tutorial will teach you how to use SQL in: MySQL, SQL Server, MS Access, Oracle, Sybase, Informix, Postgres, and other database systems.

Start learning SQL now »

示例 in Each Chapter

With our online SQL editor, you can edit the SQL statements, and click on a button to view the result.


SELECT * FROM Customers;
来试试吧 »

Click on the "来试试吧" button to see how it works.

SQL 练习

Test Yourself With 练习


Insert the missing statement to get all the columns from the Customers table.

 * FROM Customers;

Start the Exercise

SQL 示例

Learn by examples! This tutorial supplements all explanations with clarifying examples.

See All SQL 示例

SQL测验 Test

Test your SQL skills at W3Schools!

Start SQL测验!

SQL 参考

At W3Schools you will find a complete reference for keywords and function:

SQL Keyword 参考

MYSQL Functions

SQLServer Functions

MS Access功能



Data types and ranges for Microsoft Access, MySQL and SQL Server.


SQL Exam - Get Your Diploma!

W3Schools Certification

W3Schools' Online Certification

The perfect solution for professionals who need to balance work, family, and career building.

More than 25 000 certificates already issued!

Get Your 证书 »

The HTML证书 documents your knowledge of HTML.

The CSS证书 documents your knowledge of advanced CSS.

The JavaScript 证书 documents your knowledge of JavaScript and HTML DOM.

The Python 证书 documents your knowledge of Python.

The jQuery证书 documents your knowledge of jQuery.

The SQL证书 documents your knowledge of SQL.

The PHP 证书 documents your knowledge of PHP and MySQL.

The XML 证书 documents your knowledge of XML, XML DOM and XSLT.

The Bootstrap 证书 documents your knowledge of the Bootstrap framework.

W3Schools is optimized for learning, testing, and training. 示例 might be simplified to improve reading and basic understanding. Tutorials, references, and examples are constantly reviewed to avoid errors, but we cannot warrant full correctness of all content. While using this site, you agree to have read and accepted our terms of use, cookie and privacy policy. Copyright 1999-2020 by Refsnes Data. All Rights Reserved.
Powered by W3.CSS.