dual

select 'H1' as aa, 'evd00000000000' as evt_id, 'normal' as severity, 'Hello' as message, 'H1' as id, ' ' as message_group, '2020-03-20 07:16:00' as dateset
union all 
select 'H2' as aa, 'evd00000000001' as evt_id, 'normal' as severity, 'Hello1' as message, 'H2' as id, ' ' as message_group, '2020-03-20 07:16:01' as dateset

postgresql은 dual 테이블이 없다
그래서 더미 테이블을 만들때에는 dual을 그냥 빼고
sql과 똑같이 만들어준다