SQL Concat and merge values - sql

Question

How to make it correct, whats wrong with this?
SELECT Name, Surname, CONCAT(NAME + ' '+ SURNAME) 'name and surname'
FROM Worker
WHERE Born = '1988';
or
SELECT Name, Surname, 'NAME' + ' '+ 'SURNAME' AS 'name and surname'
FROM Worker
WHERE Born = '1988';

Answer 1

The standard SQL operator for concatenation is ||, so you want:
SELECT Name, Surname, (NAME || ' ' || SURNAME) as full_name
FROM Worker
WHERE Born = '1988';
Many databases also support a CONCAT() function, although logically you want at least two arguments. SQL Server uses + for string concatenation, but that is not widespread.

Answer 2

Your syntax is wrong in the two queries:
SELECT Name, Surname, CONCAT(NAME, ' ', SURNAME) "name and surname"
FROM Worker
WHERE Born = '1988';
or
SELECT Name, Surname, NAME + ' '+ SURNAME AS "name and surname"
FROM Worker
WHERE Born = '1988';
Suposing you are using Microsoft SQL Server, keep in mind there are actually few differences between regular + operator and concat() function.
concat() will implicitly converts any parameter to a string while + will throw an error if you mix strings and other types
concat() will always return a not null string even if all parameters are null. + will return null as soon as any column is null.