What does || mean in SQL ?

Question

It is written in SELECT

Answer 1

I would need to see the SQL query to be able to answer this one properly.

1. It's a string concatenation operator. It bassically appends one string to the end of another string.
Look at this link for some examples:

http://www.sqlines.com/oracle-to-sql-server/string_concat

2. It can be a logical OR operator in MySQL.

You also need to say which DBMS you are reffering to and to tag your question accordingly, so you get the best help possible. :)

Cheers! Happy learning!