db1=# explain select * from t3 join t4 on t3.name=t4.name where t4.name='ww';
QUERY PLAN
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Nested Loop (cost=0.28..17.40 rows=1 width=30)
-> Index Scan using idx_t3_name on t3 (cost=0.28..8.29 rows=1 width=15)
Index Cond: ((name)::text = 'ww'::text)
-> Seq Scan on t4 (cost=0.00..9.10 rows=1 width=15)
Filter: ((name)::text = 'ww'::text)
请问t3,t4 那个是内表，那个是外表？根据什么确定的？