If you want to select the first non-Null value of several tables:
SELECT id,
COALESCE(a.name, b.name, c.name) AS name
FROM table1 AS a
JOIN table2 AS b
ON a.id = b.id
JOIN table3 AS c USING (id)
ON a.id = c.idIf you want to select the first non-Null value of several tables:
SELECT id,
COALESCE(a.name, b.name, c.name) AS name
FROM table1 AS a
JOIN table2 AS b
ON a.id = b.id
JOIN table3 AS c USING (id)
ON a.id = c.id