=> Following are the types of join.
1. Cross Join.
2. Inner Join.
3. Outer Join.
4. Self Join.
Outer Join divide into three part.
a) Left outer join.
b) Right outer join.
c) Full outer join.
Cross Join :-
A cross join does not have a where clause. It is Cartesian product of the table. The number of rows in the first table multiplied by the number of rows in the second table.
Inner Join :-
A join that display only the rows that have a match in both joined table.
Left Join :-
Left join will display all record in left table. Unmatched rows in the right table do not appear.
Right Join :-
Right join will display all records in right table. Unmatched rows in the left table do not appear.
Full Outer Join :-
Full outer join display all record whether they are matched or not.
Self Join :-
If you want to join two instance of the same table we can use self join.
0 comments:
Post a Comment