SQL 100 - JOINs - Inner Join, Left Join, Right Join
englishspacedog YouTube tutorial from Canada
http://www.herostratus.ca/PC.htm
The 3 main kinds of SQL join are:
1) Inner Join - sees records which are in both tables
2) Left Join - sees all records in the left table
3) Right Join - sees all records in the right table
This concept is useful in Cognos, Access, and other software which uses SQL as the underlying logic.