SQL SERVER - APPLY

1. An APPLY is used to join a table-valued-function with a table. APPLY are of two types: CROSS APPLY and OUTER APPLY
   A CROSS APPLY is used when you want to return only those records from your table where a value is returned by your table valued function.
   Whereas, an OUTER APPLY is used to return all records from your table regardless of the values returned by your table valued function.
   
   
   
   SELECT name.User_Id,name.UserName,name.Email,name.MobileNo,name.VisitedDate
   FROM allocate_site lead
   outer apply dbo.fn_get_latest_response_userwise(lead.User_ID) sales 
   cross apply dbo.fn_get_user_details(lead.User_ID) name
   inner join UserDetails users on users.ID = lead.User_ID
   WHERE lead.ProductId = name.ProductID