Menu
×
   ❮   
HTML CSS JAVASCRIPT SQL PYTHON JAVA PHP HOW TO W3.CSS C C++ C# BOOTSTRAP REACT MYSQL JQUERY EXCEL XML DJANGO NUMPY PANDAS NODEJS R TYPESCRIPT ANGULAR GIT POSTGRESQL MONGODB ASP AI GO KOTLIN SASS VUE DSA GEN AI SCIPY AWS CYBERSECURITY DATA SCIENCE
     ❯   

PostgreSQL 删除列


ALTER TABLE 语句

要从表中删除一列,我们必须使用 ALTER TABLE 语句。

ALTER TABLE 语句用于在现有表中添加、删除或修改列。

ALTER TABLE 语句还用于在现有表上添加和删除各种约束。


删除列

我们想要从 cars 表中删除名为 color 的列。

要删除列,请使用 DROP COLUMN 语句

示例

删除 color

ALTER TABLE cars
DROP COLUMN color;

结果

ALTER TABLE

显示表

要检查结果,我们可以使用以下 SQL 语句显示表

示例

SELECT * FROM cars;
运行示例 »

如您在结果中看到的,color 列已从 cars 表中删除。


PostgreSQL 练习

通过练习测试自己

练习

编写正确的 SQL 语句以从表中删除一列。

cars 表中删除 year

 cars
 year;
        

开始练习


×

Contact Sales

If you want to use W3Schools services as an educational institution, team or enterprise, send us an e-mail:
[email protected]

Report Error

If you want to report an error, or if you want to make a suggestion, send us an e-mail:
[email protected]

W3Schools is optimized for learning and training. Examples might be simplified to improve reading and learning. Tutorials, references, and examples are constantly reviewed to avoid errors, but we cannot warrant full correctness of all content. While using W3Schools, you agree to have read and accepted our terms of use, cookie and privacy policy.

Copyright 1999-2024 by Refsnes Data. All Rights Reserved. W3Schools is Powered by W3.CSS.