Given this query,
LEFT JOIN b ON b.a_id = a.id
LEFT JOIN c ON c.a_id = a.id
HAVING COUNT(DISTINCT b.id) < COUNT(DISTINCT c.id)
if b is a significantly larger table than c, will there be performance implications to the order I do the joins? I read somewhere that the rule of thumb is to join smallest to largest, but that might've been referring to INNER JOINs.
I realize that the results will depend on the order of outer joins in many scenarios, but in one like the above where the order doesn't matter for veracity, will it likely affect performance?