sql - can we replace full join with union of left and right join? why not? -
can replace full join union of left , right join? if no,why? 'yes' if t1 , t2 sets (no duplicated rows), otherwise answer 'no'. create table t1 (i int); create table t2 (i int); insert t1 values (1); insert t1 values (2); insert t1 values (2); insert t2 values (3); full join select * t1 full join t2 on t1.i=t2.i order 1,2 1 (null) 2 2 2 2 (null) 3 union select * t1 left join t2 on t1.i=t2.i union select * t1 right join t2 on t1.i=t2.i order 1,2 1 (null) 2 2 (null) 3 union all select * t1 left join t2 on t1.i=t2.i union select * t1 right join t2 on t1.i=t2.i order 1,2 1 (null) 2 2 2 2 2 2 2 2 (null) 3

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