Pick a join type and watch three things update together: the Venn diagram, the SQL statement, and the actual result table computed from the sample data below. Edit any cell in the sample tables and the result recomputes instantly. Nothing leaves this page.
Sample tables (click any cell to edit)
users (left table)
id
name
remove
orders (right table)
id
user_id
item
remove
The sample data includes a user with no orders (Carol) and an order whose user_id matches no user (user_id 9). That is exactly where the join types differ.