Connection query for 3 tables in SQL

Two kinds:
1.select * FROM table 1, table 2, table 3 where table 1. field = Table 2. field and table 1. field = Table 3. Field
This efficiency is smaller than the lower structure of simple data can be used
2.select * FROM table 1 join table 2 on table 1. field = Table 2. field and join Table 3 on table 1. field = Table 3. Field
This is good.

Questioner evaluation

2nd and join is wrong, should be join, no and


Http://zhidao.baidu.com/link?url=jI4ahWhPIbnq6gXcOZHWAeUPwSmO211KYDG2VfE0FvmRAGVAX7jVgwoVNK2JrroSr-HVKRq7vBVmQFki2JfwRK

Connection query for 3 tables in SQL