Lateral
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select * from bys_test_tobe.testEvent t1
left join
(
select * from bys_test_tobe.testEvent t2
where t2.date_at > t1.date_at
order by t2.date_at asc
limit 1
) t2 on t1.id = t2.id
ERROR 발생:
SQL Error [42P01]: ERROR: invalid reference to FROM-clause entry for table “t1”
Hint: There is an entry for table “t1”, but it cannot be referenced from this part of the query.
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select * from test t1
left join lateral
(
select * from test t2
where t2.date_at > t1.date_at
order by t2.date_at asc
limit 3
) t2 on true;
lateral 은 외부 스코프에 접근이 가능하여 사용 가능하다.
