How to search a Table using a condition from another table?

Question

SQL

How can I write a SQL query like this
SELECT * FROM table1 WHERE id = table2.pid
So that I can select fields from table 1 where the ID value is equal to the PID value in table 2

Answer 1

SELECT * FROM t1
WHERE id in (SELECT id FROM t2)

Answer 2

select
  t1.*
from
  table1 t1,
  table2 t2
where
  t1.id = t2.pid;