Join between 2 tables A and B can be represented pictorially as given below:
INNER JOIN :
LEFT OUTER JOIN or LEFT JOIN:
RIGHT OUTER JOIN or RIGHT JOIN:
FULL OUTER JOIN or FULL JOIN:
FULL OUTER JOIN WHERE A IS NULL or B IS NULL
INNER JOIN :
LEFT OUTER JOIN or LEFT JOIN:
RIGHT OUTER JOIN or RIGHT JOIN:
FULL OUTER JOIN or FULL JOIN:
FULL OUTER JOIN WHERE A IS NULL or B IS NULL
