select a1.id,a1.x,a1.y.b1.z
from (select b.id,a.x,b.y
from a,b
where a.id =* b.id and b.m =n) a1,
(select b.id,c.z
from b,c
where b.id *=c.id and b.m =n) b1
where a1.id=b1.id
from (select b.id,a.x,b.y
from a,b
where a.id =* b.id and b.m =n) a1,
(select b.id,c.z
from b,c
where b.id *=c.id and b.m =n) b1
where a1.id=b1.id
FROM A INNER/LEFT/RIGHT JOIN B ON A.id = B.id
INNER/LEFT/RIGHT JOIN C ON A.id = C.id
FROM A INNER JOIN B ON A.id = B.id
INNER JOIN C ON A.id = C.id
FROM B INNER JOIN A ON B.id = A.id
INNER JOIN C ON B.id = C.id
WHERE B.m=n