SQL SERVER PART II

 Hey Guys, I hope that you are enjoying with my blogs writing and today's we will cover some  "SQL SERVER" Concepts.

Microsoft SQL Server is a relational database management system, or RDBMS, developed and marketed by Microsoft.

As a database server, it is a software products with primary function of storing and retrieving data as requested by other software application.

Initial Releases is April 24, 1989;

   SQL UNION OPERATOR:

• The union operator is used to combine the result-set of two or more select statements.
• Every select statements within union have the same number of columns
• The columns also have similar data type
• The columns in every select statement must also be in the same order

                         

• Syntax: 
• For Distinct Contents: 

        select column_name(s) from table1 union select column(s) from table1;

        For Example: 

                              Input:

    select Id, FirstName, LastName from tblCustomer1

union

select Id, FirstName, LastName from tblexpired

                                Output:

• For All Contents:

        select column_name(s) from table1 union select column(s) from table1;

          For Example: Input

 select Id, FirstName, LastName from tblCustomer1

union all

select Id, FirstName, LastName from tblexpired

                                Output: Both table has mentioned above and we have taken UNION ALL.

                             Note: We can indicate content by using as normal and expired or anything like:

select 'nomal' as type1, Id, FirstName, LastName from tblCustomer1

union all

select 'expired' as type1,Id, FirstName, LastName from tblexpired

• GROUP BY:
•  This statement is often used with aggregate function(COUNT(),MAX(), MIN(),SUM,AVG()).
• For Example: we have created a table "tblCustomer_ctry" by using this aggregate function we will find its sum of sales of two Countries.
• "tblCustomer_ctry"    
  
  
  

        Input:  select count(Id), sum(sales),Country from tblCustomer_ctry

                  group by country

      Output:

SUBQUERY: A subquery is a query within another SQL query and embedded within WHERE clause.

•  It is also called Nested Query.
• In this case firstly executes its inside queries and after that outside queries.
• Above two table has created tblCustomer and tblAddress .

            Input: select * from tblAddress

                      where CustomerId_fk in

                      (select Id from tblCustomer)

     Co-related queries : In this Queries ,first executes outside queries and send        the data for inside execution and again send the data from inside to outside. 

            Input: select * from tblAddress

                      where CustomerId_fk in

                      (select Id from tblCustomer where Id=CustomerId_fk)

                                             Thank You...