The DUAL is special one row, one column table present by default in all Oracle databases. We cannot insert, update, delete record in dual table. Dual means dummy. In the dual table only one column is ...

Alternatively, you can select a constant, pseudocolumn, or expression from any table, but the value will be returned as many times as there are rows in the table. Refer to " [About SQL Functions] ...

Dual table:dual table is a dummy table whichcontains one row and one column andby default it is present indatabase.it contains a singlevarchar2(1) column known as dummywith a value "x".it can be ...