oarcle插入当前时间
时间: 2023-09-30 19:05:03 浏览: 32
在Oracle中,可以使用SYSDATE函数插入当前时间。例如,可以使用以下语句向表中插入当前时间:
```
INSERT INTO table_name (column1, column2, date_column)
VALUES ('value1', 'value2', SYSDATE);
```
其中,date_column是一个日期类型的列,它将插入当前时间。注意,SYSDATE函数返回系统当前日期和时间,以日期时间格式返回。
相关问题
oarcle with recursive
`WITH RECURSIVE` is a SQL clause that allows for recursive queries to be made. The `WITH RECURSIVE` clause defines a recursive common table expression (CTE), which is a temporary named result set that can be referenced within the main query.
In the context of Oracle, the `WITH RECURSIVE` clause is not supported natively. However, there are workarounds that can be used to achieve similar functionality. One common method is to use a hierarchical query with the `CONNECT BY` clause.
Here's an example of a recursive query using `CONNECT BY`:
```
WITH
data(id, parent_id, name) AS (
SELECT 1, NULL, 'Root' FROM DUAL UNION ALL
SELECT 2, 1, 'Child 1' FROM DUAL UNION ALL
SELECT 3, 1, 'Child 2' FROM DUAL UNION ALL
SELECT 4, 2, 'Grandchild 1' FROM DUAL UNION ALL
SELECT 5, 3, 'Grandchild 2' FROM DUAL
)
SELECT id, parent_id, name, LEVEL
FROM data
CONNECT BY PRIOR id = parent_id
START WITH parent_id IS NULL;
```
This query returns a hierarchical result set that represents a tree structure. The `CONNECT BY` clause specifies the join conditions between parent and child rows, and the `START WITH` clause specifies the root of the tree. The `LEVEL` pseudo-column is used to display the depth of each row in the tree.
oarcle数据库服务器备份
你好,关于oracle数据库服务器备份,我可以为您提供一些基本的信息和建议。首先,备份是保障数据安全的重要手段之一,建议您定期进行备份,并将备份数据存储在安全可靠的地方。其次,备份方式可以选择全量备份或增量备份,具体选择哪种方式需要根据实际情况和需求来确定。最后,备份过程中需要注意数据一致性和备份文件的完整性,以确保备份数据的可靠性和可恢复性。希望这些信息对您有所帮助。