How can SQL combine two fields into one field?

In SQL, the CONCAT function can be used to combine two fields into one field. For example, if there is a students table with fields for first_name and last_name, the following SQL statement can be used to merge these two fields into a field called full_name:

SELECT CONCAT(first_name, ' ', last_name) AS full_name
FROM students;

This will combine the values of first_name and last_name into the full_name field, adding a space between them.