Join:It is the combining of two rows from different tables 
based on the comparative values in selected columns.

Types of Join : Cross Join, Inner Join or equi join and 
Outer Join which comprises of Left join and Right join.

Inner Join : It is used to select certain fields from both 
tables and only correct rows will be joined together.
Sytax:SELECT <column_name> FROM <Table1>, <Table2> WHERE 
(Table1.column = Table2.column)

Outer Join:
  Left join: It returns all the data's from the table 
present in left of the join and only those data's from the 
right tabel which matches the condition.
  Syntax:SELECT <column_name> FROM <Table1> LEFT JOIN 
<Table2> ON Table1.column = Table2.column (Conditions like 
WHERE and USING)

  Right join: It returns all the data's from the table 
present in right of the join and only those data's from the 
left tabel which matches the condition.
  Syntax:SELECT <column_name> FROM <Table1> LEFT JOIN 
<Table2> ON Table1.column = Table2.column (Conditions like 
WHERE and USING)