What Does Concatenation Mean?
Concatenation, in the context of databases, refers to the joining together two or more things into a large one. In database parlance, the things being joined are generally two table fields which may be from the same or different tables.
Techopedia Explains Concatenation
The most common use of concatenation is to join two database fields that are stored separately but usually operated upon together. Take for example to fields named ‘FIRST NAME’ and ‘SURNAME’. These two fields are sometimes as two stored separate fields, but when retrieving them the viewer will usually want to see both names.
Concatenation is achieved by use of a special concatenation operator in a SQL query. For example, Oracle Database uses the || operator to join two strings. A sample SQL query to achieve this is:
SELECT first_name||’ ‘||surname FROM customer_master.
Note that in this case we have also included a space (enclosed by ‘ ‘) between the two names. This is simply to enhance the legibility of the final output. If we just joined the two fields without a space in between the query would be:
SELECT first_name||surname FROM customer_master.