Two types of joins
1. Inner Join
2. Outer Join
   2.a Left outer join
   2.b Right outer join

Inner Join
Outer join
self join
cross join

Joins means if we want data from multiple tables we can use 
joins.
and for ommit the cartisian product we can use joins

we r having diff types of joins
simple joins
inner join
outer join
left outer join
right outer join

In SQL Server, we have the following joins
1.Self Join 
2.Inner Join
3.Cross Join
4.Outer Join
4.1 Left Outer Join
4.2 Right Outer Join
4.3 Full Outer Join

1)Simple Join
              a)Equi join
              b)Non Equi-join
2)Self join
            
3)Outer Join

2 types:
  1. Inner Join
  2. Outer Join
  3. Cross Join
1. Inner Join: Inner Join displays matched rows.
2. Outer Join: Outer Join displays matched rows as well as 
unmatched rows. Outer Joins again classifed into 3 types.
  2a. Left Outer Join: Matched rows as well as left table 
unmatched rows.
  2b. Right Outer Join: Matched rows as well as right table 
unmatched rows.
  2c. Full Outer Join: Matched rows as well as left table 
unmatched rows and right table unmatched rows.
3. Cross Join: It will display the cartegion product of the 
tables.

1)Inner Join
  - Natural Join
  - Cross Join
2)Outer Join
  - LEFT Outer Join
  - RIGHT Outer Join
  - FULL Outer Join
3)Merge Join
4)Hash Join
5)Sort-Merger Join

equi join
non equi join
left outer join
right outer join

that's it ok......

1)Inner join   A join that displays only the rows that have 
a match in both joined tables
2)Outer join   A join that includes rows even if they do 
not have related rows in the joined table
	i) Left outer join   All rows from the first-named 
table 
	ii) Right outer join   All rows in the second-named 
table 
	iii) Full outer join   All rows in all joined 
tables are included
3)Cross join   A join whose result set includes one row for 
each possible pairing of rows from the two tables

http://msdn2.microsoft.com/en-us/library/zt8wzxy4
(VS.80).aspx