select a.id, t1.column_1, t2.column_2from ( select id from t1 union select id from t2) aleft outer join t1 on a.id = t1.idleft outer join t2 on a.id = t2.id
select a.id, t1.column_1, t2.column_2from ( select id from t1 union select id from t2) aleft outer join t1 on a.id = t1.idleft outer join t2 on a.id = t2.id
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