Concatenation Operator in SELECT statement

A concatenation operator:

• Concatenates columns or character strings to other columns.
• is represented by two vertical bar ( || )
• Creates a resultant column that is character expression.

Using the Concatenation Operator:

In the above example ename and job are concatenated, and they are given alias Employees. Notice that the ename and job code are combined to make a single output column.

The AS keyword before the alias name makes the SELECT clause easier to read.