Answer Posted / vikneswaran

no,union all and natural join is not same. for example tave
two tame emp and dept

emp table

empid ename salary
1 a 1000
2 b 2000

dept table
deptid deptno
1 10
2 20
if i join this two tables
(empid = deptid)

empid ename salary deptno
1 a 1000 10
2 b 2000 20

if i union a11 this two tables

empid ename salary deptno
1 a 1000 null
2 b 2000 null
1 null null 10
2 null null 20
so join and unionall is not same

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