Question

What are the potential pros and cons of each of these queries given different databases, configurations, etc? Is there ever a time when one would be more efficient than the other? Vice versa? Is there an even better way to do it? Can you explain why?

Query 1:

SELECT    * FROM   table_a, table_b, table_c WHERE   table_a.id = table_b.id AND   table_a.id = table_c.id AND   table_a.create_date > DATE('1998-01-01'); 

Query 2:

SELECT    * FROM   table_a  INNER JOIN table_b ON   table_a.id = table_b.id INNER JOIN table_c ON   table_a.id = table_c.id WHERE   table_a.create_date > DATE('1998-01-01'); 

Answer 1

Same query, different revision of SQL spec. The query optimizer should come up with the same query plan for those.