example of many to many relationship
Example: how to join tables with many to many relationships
SELECT
p.person_id,
p.name,
a.conference,
b.publication
FROM
person AS p
LEFT JOIN (SELECT
pc.person_id,
c.conference
FROM
person_conference AS pc
INNER JOIN conference AS c
ON pc.conference_id = c.conference_id) AS a
ON p.person_id = a.person_id
LEFT JOIN (SELECT
pp.person_id,
ppp.publication
FROM
person_publication AS pp
INNER JOIN publication AS ppp
ON pp.publication_id = ppp.publication_id) AS b
ON p.person_id = b.person_id