how to write a query ?

First, if your table field is called "wdate", why do you try to write a query that uses the field "time_stamp"?
Second, you need a value called "Amount" in your output. Where is it in your database?

1,column name changed, 
2, the amount should calculated based on the count ( for  ex if count(an,fn)=1, amount 300,else 350)