Applying Concatenation Operator :

The concatenation operator links column to other columns, arithmetic expressions, constant values.
Columns on either side of the operator are combined to make a single output column.
The resultant column is treated as an character expression.
The concatenation operator is represented in oracle by double pipe symbol ( || )

Example :

Select Empno||' '||Ename||' '||',designation is '||Job" Employees Informtion" From Emp;