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  • SQL Views

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    A view is a virtual table which is stored in database with an associated name .Using views query we can select specific data from a large table . Suppose there is large database of any college , so i want to view the records of any one branch from that database , this can be done with the views query . view can be create from a single table , multiple table and another view .
    Syntax :

    select view view_name select column1 , column2 ....columnN from table_name where clause ;
    

    Example :
    Table name : Employee_Info

      Id        Employee_name          Employee_Age         Employee _Salary     City 
      1            Mukesh                  23                  120000            Meerut
      2            Ayush                   24                  200000            Baroda
      3            Ishan                   40                  400000            Multan
      4            Pranav                  35                  123,00000         Dehradun
      5            Abhishek                26                  800000            Mussoorie
      6            Ravi                    25                  300000           Pauri-Garhwal
      7            David                   40                  8000              Baghpat
    

    Query : To create view

    create view Employee_view as select Name , Age from Employee_Info ;
    

    Query : Query to retrieve records from Employee_view .

    select * from Employee_view
    

    Output :

     Employee_name          Employee_Age 
      Mukesh                  23 
      Ayush                   24   
      Ishan                   40                  
      Pranav                  35                 
      Abhishek                26                  
      Ravi                    25                 
      David                   40   
    

    Query : Query to Update Employee_view .

    update Employee_view set age = ' 50 ' where name = ' Ravi ' ;
    

    Output :

     Employee_name          Employee_Age 
      Mukesh                  23 
      Ayush                   24   
      Ishan                   40                  
      Pranav                  35                 
      Abhishek                26                  
      Ravi                    50    // row affected             
      David                   40   
    

    Query : Query to Drop Employee_view .

    drop view Employee_view ;
    

    Output :It delete the Employee_view
    Query : Query to Delete row from Employee_view .

    delete from Employee_view where age = ' 50 ' ;
    

    Output :Ravi row has been deleted

     Employee_name          Employee_Age 
      Mukesh                  23 
      Ayush                   24   
      Ishan                   40                  
      Pranav                  35                 
      Abhishek                26                                   
      David                   40   
    

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