Author: Shikha Katariya
Set Operators
Defining Set Operators: Set Operators combine the Result Set of two or more SELECT queries into a single result. The query containing the set operator is called Complex Query. Key Facts about Set Operators...
Joins in SQL
What are Joins ? Joins may be defined as SQL queries, which are used to combine rows from two or more tables or views based on the relationship between the tables. Why and When...
Correlated Sub Queries.
Unlike the normal Subqueries, the Correlated Subqueries can also be defined as Inner Query embedded in an Outer Query. But the main difference between Correlated and Uncorrelated or normal Subquery is –
Sub Queries [ Uncorrelated Sub Queries ]
A Subquery as the name suggests , is an Inner Query nested or embedded within another SQL Query also called Outer Query. Key Facts about Sub Queries. The Inner Query or the Subquery...
Views
Understanding Views: To understand views let’s take an e.g. of a mirror from our day to day life. We can see exact replica of ourselves in the mirror i.e. Virtual image. View is a also...
Indexes
Understanding Indexes : To understand what are Indexes, let’s take a very common example of Index at the back of a book. In Book, Index displays the reference page number for each topic.For...
Introduction..
No Business can run without DATA. Infact ,the success of any business organization depends upon how effectively it analyzes and acts on data. But , How Data is important for Business ? The Success...
Data Definition Language ( DDL Commands )
What are DDL Commands ?? Data Definition Language ( DDL Commands ) as the name suggests , are used to define and modify the database objects definitions. They are auto – saved or Auto –...
SQL Statements .
What are SQL Statements ?? SQL Statements are basically commands that are used for : Defining the database objects Manipulating the data Controlling the transactions Deciding the access level of the users for database...