如何执行ALTER TABLE查询? [英] How to execute an ALTER TABLE query?

问题描述

我有一个名为tbl的SQL表，我试图向其中添加列A，B和C.

I have an SQL table called tbl, im trying to add the columns A, B and C to it.

当我执行命令时:

String addcolumns = "ALTER TABLE SqlCreatedTbl ADD  A char(50) ;";
                        ......
             cmd = new SqlCommand(addcolumns, conn);
             conn.Open();
             cmd.ExecuteNonQuery();

该列已添加！

但是，当我尝试添加多列时，它不起作用，这给了我一个错误.用于添加多列的命令im编写如下:

However, when i try to add multiple columns, it does NOT work, it gives me an error.. the command im writting for adding multiple columns is the following:

addcolumns = "ALTER TABLE SqlCreatedTbl ADD  ( A char(50),  B char(50), C char(50) );";

调试器突出显示以下行: cmd.ExecuteNonQuery(); 并引发以下异常:

the debugger highlights the line : cmd.ExecuteNonQuery(); and throws the following exception:

异常详细信息:System.Data.SqlClient.SqlException:'('附近的语法不正确.

Exception Details: System.Data.SqlClient.SqlException: Incorrect syntax near '('.

推荐答案

如果要与SQL Server数据库进行交互(使用T-SQL)，则即使添加多个列，也不能在列定义列表中加上括号:

If you're interacting with an SQL Server database (using T-SQL), you must not place parentheses around your list of column definitions even when adding multiple columns:

ALTER TABLE SqlCreatedTbl ADD A char(50), B char(50), C char(50);

这篇关于如何执行ALTER TABLE查询?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！