[SQL] Function to return a multiple colmn table or view

[Wilkinson, Jim]

I am new to psql , so please be patient !

Can someone please provide a small quick example of a a function that
take 1 paramater and based on that parameter, returns a table or view ?

Etc ....  Note this is just a abstract of the functon, not a working
function call !!!

Create function viewtest( start_month) 

        If $1 = 'April'
        Then 
        Select * from april_view;
        Return ;

Let me know  how to do this.

Thanks