What is the method for concatenating strings in Oracle?

In Oracle databases, string concatenation is usually done using the concatenation operator “||”. Here are some examples:

1. Join the two strings together using a connector.

SELECT 'Hello ' || 'World' FROM dual;

Output: Greetings Earth

1. Concatenating column values and strings.

SELECT first_name || ' ' || last_name FROM employees;

Output: John Doe

1. Concatenate column values, strings, and function results.

SELECT 'Dear ' || first_name || ', your salary is ' || salary || '.' FROM employees;

Dear John, your salary is 5000.

or

Dear John, your monthly income is 5000.

Please note that in Oracle, the string concatenation operator is non-standard; other databases may use different operators or functions to achieve string concatenation.