T-sql get min and max value for each day

Question

I am trying to write a query where for each day I get the minimum and maximum price for each item from price details table.

In price details table prices are set mul

Answer 1

A simple group by should work:

select  cast(price_set_date as date) as [Date]
,       exch_ticker 
,       min(buy_price) as MinPrice
,       max(buy_price) as MaxPrice
from    price_details as p
group by 
        exch_ticker
,       cast(price_set_date as date)

Not sure why your example query is using a self join. If there's a good reason please add an explanation to your question.