Oracle Dual Table

Dual is a virtual table with only one column.

You need to use this table when querying for time or date objects.

For example: select Sysdate from dual;

Because in Oracle, the query statement must have a keyword select ... from tablename; Only the sample statement is complete. If you do not have a table name, you cannot query. When the time and date are not in any table, the concept of dual virtual table is introduced at this time.

Select User from dual;--returns the currently connected user