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So often I need to query several table that are linked through some key.I never understood the difference between different types of JOIN although I used it in one of my application, but it just worked without knowing how.The main problem with using the wrong JOIN is that you get lots of duplicated records no matter you try to filter the results using WHEREMy question is general and not specific to a certain case. I only need to understand the difference between the different types of Join.Can any expert help me?Thanks
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A view can be created as Create view view_name as <query>Primarily 2 important advantages can be achieved if one provides access through Views and not through actual Tables:-1) Added security- One can always restrict a user from viewing certain things by creating a view that we wish to allow the users to see and not the ones that are secured enough to let users to. One can grant permissions to views itself.2) Simple presentation- We can always remove complexity of data to be viewed by users by creating views and let them selecting data from views and not the actual table.So that they don't get confused by seeing extra fields that the user hasn't intended to see.
