- A dual table is oracle’s in built table.
- It can be used for arithmetic calculations.
- We can retrieve data from the dual table but cannot insert the data.
- It has only single row and signal column.
- Structure of dual table is as follow.
- DESC dual;
- Column name is dummy with data type varchar2 and size=1.
- It contains value ‘X’.
SELECT 20*7 FROM DUAL; SELECT sum(10,20,30) FROM DUAL; SELECT max(10,20,30) FROM DUAL;