It is used to preserve the missing information resulting from natural join OR inner join.
R1 table
A B C
X 10 100
Y 20 100
Z 30 200
S 40 400
R2 table
C D
100 L
200 M
300 N
100 T
Missing element in natural join.
Left outer join
Natural Join + Missing information LHS
Output
A B C D
X 10 100 L
Y 20 100 L
Z 30 200 M
X 10 100 T
Y 20 100 T
S 40 400 -
Right outer join
Natural Join + Missing information RHS
Output
A B C D
X 10 100 L
Y 20 100 L
Z 30 200 M
X 10 100 T
Y 20 100 T
- - 300 N
Full outer join
Natural Join + Missing information LHS + Missing information RHS
Output
A B C D
X 10 100 L
Y 20 100 L
Z 30 200 M
X 10 100 T
Y 20 100 T
- - 300 N
S 40 400 -
Copyright ©2022 coderraj.com. All Rights Reserved.