sql添加列_SQL添加列操作
sql添加列
This article explains the SQL add column operation into an existing SQL table. We will also explore different examples of SQL add column operations.
本文介绍了对现有SQL表SQL添加列操作。 我们还将探讨SQL添加列操作的不同示例。
Sometimes we want to add columns into an existing table. In existing tables, we might have records in it. We do not want to lose existing data as well. In many circumstances, we can drop the tables and recreate them but this is not recommended generally, especially in a production environment, as it can be destructive as it pertains to data. We can still perform a SQL add column operation using Alter Table command, which avoids have to drop tables, delete data, even if only temporarily.
有时我们想将列添加到现有表中。 在现有表中，我们可能有记录。 我们也不想丢失现有数据。 在许多情况下，我们可以删除表并重新创建它们，但是通常不建议这样做，尤其是在生产环境中，因为它与数据有关可能具有破坏性。 我们仍然可以使用Alter Table命令执行SQL添加列操作，这避免了必须删除表，删除数据（即使只是暂时的）。
sql添加列 This article explains the SQL add column operation into an existing SQL table. We will also explore different examples of SQL add column operations. 本文介绍了对现有SQL表SQL添加列操作。 我们还将探讨SQL添加列操作的不同示例。 Sometimes we want to add columns into an existing table. In existing tables, we might have records in it. We do not want to lose existing data as well. In many circumstances, we can drop the tables and recreate them but this is not recommended generally, especially in a production environment, as it can be destructive as it pertains to data. We can still perform a SQL add column operation using Alter Table command, which avoids have to drop tables, delete data, even if only temporarily. 有时我们想将列添加到现有表中。 在现有表中，我们可能有记录。 我们也不想丢失现有数据。 在许多情况下，我们可以删除表并重新创建它们，但是通常不建议这样做，尤其是在生产环境中，因为它与数据有关可能具有破坏性。 我们仍然可以使用Alter Table命令执行SQL添加列操作，这避免了必须删除表，删除数据（即使只是暂时的）。