background
Now there is a user table t_userwith three fields, id, name, sex.
| id | name | sex |
|---|---|---|
| 1 | Zhang San | male |
Executed the update statement and 张三changed it to 李四(just a simple simulation here, don't laugh), and then we want to see what his previous name was
View data before updating or deleting
The code is directly written here, which is very simple. The code to view the data in the table three minutes ago is as follows:
select * from t_user AS OF TIMESTAMP SYSDATE-3/1440 where id = '1'
The result is as follows:
| id | name | sex |
|---|---|---|
| 1 | Zhang San | male |
Here is the explanation of sql:
SYSDATE : current time
1440 ：24h*60m=1440m
3: 3 minutes ago
It should be noted here that do not use aliases, an error will be reported.
We have been able to query his previous data, and it is not difficult to change it back, so I will not introduce it here.