Let me start by saying that you have ressurected a 3 year old topic. You should have read the warning and let it be. Especially when you don't really know what you are talking about.
The plus symbol (+) has 2 functions:
a) to add when used with numbers
b) to concatenate when used with strings.
The post that you've commented includes a space within quotes, so at best it will produce an error if the Tel_H_Code or Tel_H is a number. If they have been declared as chars then it will just concatenate them.
This worked to combine 2 string values (first name & last name) from 2 separate columns (first_name, last_name) into 1 new column (full_name). Straight out of the textbook: SQL Fundamentals 3rd edition pg. 344:
select employee_id, first_name || ' ' || last_name AS full_name, hire_date
I've developed an app that takes the data in a text file and moves it to specific columns in an Excel file. My computer has the Excel 2010 installed. So the application works fine with no issues. However we've begun to upgrade computers and software in the office ...