Why do we require Databases and SQL ?

1. Manageability: To maintain large amount of data in structured format. Databases contain one or more tables which in turn consists of records and attributes.

2. Security: Data should be accessed only to authorized users and to authorized applications.

3. Integrity: Data should be authentic at any given point of time. Database allows data integrity to be maintained with the help oif multiple tactics.

4. Processing: Databases allows access to portion of data, which means that faster access techniques and which further means good user experience.

5. Structure: Databases allow right structure to store large volume of data. 

All these steps require expertise and we deliver course which combines all of this.

Various types of joins

1. Inner Join: When 2 or more tables are joined, only common records are returned where a specific column is present in all the in-scope tables.

2. Outer Join: When 2 or more tables are joined, all records and all columns in both the tables are returned.

3. Left Join: When 2 or more tables are joined, common records are returned along with all records from table mentioned on the left hand side.  This join operation is performed on a specific column which is present in all the in-scope tables.

4. Right Join: When 2 or more tables are joined, common records are returned along with all records from table mentioned on the right hand side.  This join operation is performed on a specific column which is present in all the in-scope tables.

5. Self Join: When a join operations is performed between same table. This self join is very useful when any one wants to compare records within the same table.