如何在 Oracle 数据库中创建临时表?

问题描述

我想在 Oracle 数据库中创建一个临时表

I would like to create a temporary table in a Oracle database

类似的东西

Declare table @table (int id)

在 SQL 服务器中

然后用select语句填充它

And then populate it with a select statement

有可能吗?

谢谢

推荐答案

是的，Oracle 有临时表.这是AskTom<的链接/a> 描述它们的文章，这里是官方的 oracle CREATE表格文档.

Yep, Oracle has temporary tables. Here is a link to an AskTom article describing them and here is the official oracle CREATE TABLE documentation.

但是，在 Oracle 中，只有临时表中的数据是临时的.该表是其他会话可见的常规对象.在 Oracle 中频繁创建和删除临时表是一种不好的做法.

However, in Oracle, only the data in a temporary table is temporary. The table is a regular object visible to other sessions. It is a bad practice to frequently create and drop temporary tables in Oracle.

CREATE GLOBAL TEMPORARY TABLE today_sales(order_id NUMBER)
ON COMMIT PRESERVE ROWS;

<小时>

Oracle 18c 添加了私有临时表，它们是单会话内存对象.请参阅 文档 了解更多详情.可以动态创建和删除私有临时表.

Oracle 18c added private temporary tables, which are single-session in-memory objects. See the documentation for more details. Private temporary tables can be dynamically created and dropped.

CREATE PRIVATE TEMPORARY TABLE ora$ptt_today_sales AS
SELECT * FROM orders WHERE order_date = SYSDATE;

<小时>

临时表很有用，但它们在 Oracle 中经常被滥用.通常可以通过使用内联视图将多个步骤组合到单个 SQL 语句中来避免它们.

Temporary tables can be useful but they are commonly abused in Oracle. They can often be avoided by combining multiple steps into a single SQL statement using inline views.

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