Update show-drop-databases.md

Author: soyeric128

docs/en/sql-reference/10-sql-commands/00-ddl/00-database/show-drop-databases.md

@@ -7,6 +7,9 @@ import FunctionDescription from '@site/src/components/FunctionDescription';
 
 Lists all databases along with their deletion timestamps if they have been dropped, allowing users to review deleted databases and their details.
 
+- Dropped databases can only be retrieved if they are within the data retention period.
+- It is recommended to use an admin user, such as `root`. If you are using Databend Cloud, use a user with the `account_admin` role to query dropped databases.
+
 See also: [system.databases_with_history](../../../00-sql-reference/20-system-tables/system-databases-with-history.md)
 
 ## Syntax