Online SQL generator Concat operator?

[SoSadatSQL]

Can anyone please tell me why this will not return a concatenated field in the online SQL generator:

SELECT FirstName+ ' ' +LastName
FROM Customer;

I thought this was supposed to combine two colums. I also tried: SELECT City+ ', ' +State+ ' ' + CAST (PostalCode AS CHAR (5))
FROM Customer;

and

SELECT RTRIM (FirstName) & ' ' & LastName
FROM Customer;

and

SELECT CONCAT (FirstName, " ", LastName)
FROM Customer;


Thanks!

SoSadatSQL

[rmiao]

First two work in sql server. Which rdbms did you use? Got any error?

[SoSadatSQL]

I'm trying to use this online thing that is used for the online course:

http://sqlcourse.com/cgi-bin/interpreter.cgi

I have no idea why, none of those options will work.

[rmiao]

Don't know what's that, test sql query in rdbms you use.