Joins are used to combine records from two or more tables in a database. A JOIN is means for combining fields from two tables by using values common to each.
To join the tables there must be common column( different name but definition must be same) in those tables.
Types of joins
- Left Join
- Right Join
- Full Outer Join
- Self Join
The INNER JOIN keyword selects all records from both tables as long as there is a matched records between the columns in both tables.
The most frequently used and important of the joins is the INNER JOIN. They are also referred to as an EQUI JOIN.