1. A SQL join clause combines columns from one or more tables in a relational database. It creates a set that can be saved as a table or used as it is. A JOIN is a means for combining columns from one (self-table) or more tables by using values common to each.
2. A JOIN clause is used to combine rows from two or more tables, based on a related column between them.
https://en.wikipedia.org/wiki/Join_(SQL)#Inner_join (1.); https://www.w3schools.com/sql/sql_join.asp (2.)
Author: David Khedr