table1 to table2 is one-to-many
table2 to table3 is one-to-one
Looks like you want records from table 3 when you don't have any records in table 2 (no children).
This would only be possible when you have some sort of direct relationship between table1 and table 3 (probably one-to-many).
Cheers, Joy [SCJP 1.4, SCBCD 5.0]
get high on alcohol, algorithm or both