I've been thinking, which SELECT statement is better for readability and optimizing? Since the 2.x era i've been modeled into using the WHERE statment.

SELECT * ;
from a,b,;
b outer join c on b.key2=c.key2
where a.key1=b.key2

OR


SELECT * ;
from a inner join b on a.key1=b.key1,
b outer join c on b.key2=c.key2