How can you create a relationship between two Data Extensions?

if you want to combine or join two data extension together, you can relate them in the selected data sources section of your selection these relations are created by dragging one data extension on top of another in the selected data sources section, and defining how they are connected choose the field in the first data extension that matches the field in the second data extension usually, this will be an id or email address field in deselect segment, we call these the matching columns choose an option in the dropdown in the middle below is a list of the available options for how the data extensions should relate to each other in deselect segment, we call these the matching types in sql, these are the joins name description example sql query a with/without matching b match or don’t match de a with de b returns a list of contacts (a) combined, whether or not they have a matching account (b) left join a with matching b only match de a with de b return only the contacts (a) that have a matching account (b) inner join b with/without matching a match or don’t match de b with de a return all accounts (b) whether or not they have matching contacts (a) right join a with all b match all of de a with de b return all contacts (a) with all accounts (b) full outer join a without matching b de a without de b return the contacts (a) that don’t have a matching account (b) left join where b is a null value b without matching a de b without de a return the accounts (b) that don’t have a matching contact (a) right join where a is a null value