cross-join

问题 I have 5 items each of which can take on the value of 1 or -1. I want to generate a matrix that consists of rows of the possible combinations. The order of the items does not matter and the order of the combinations does not matter. I know I could do this mechanically, but I thought that someone must know a shortcut to generating this matrix. I apologize if this is similar to other questions but none of the solutions I have found can be applied to this particular problem with my programming

问题 What is the difference between CROSS JOIN and INNER JOIN ? CROSS JOIN: SELECT Movies.CustomerID, Movies.Movie, Customers.Age, Customers.Gender, Customers.[Education Level], Customers.[Internet Connection], Customers.[Marital Status], FROM Customers CROSS JOIN Movies INNER JOIN: SELECT Movies.CustomerID, Movies.Movie, Customers.Age, Customers.Gender, Customers.[Education Level], Customers.[Internet Connection], Customers.[Marital Status] FROM Customers INNER JOIN Movies ON Customers.CustomerID

问题 What is the difference between CROSS JOIN and INNER JOIN ? CROSS JOIN: SELECT Movies.CustomerID, Movies.Movie, Customers.Age, Customers.Gender, Customers.[Education Level], Customers.[Internet Connection], Customers.[Marital Status], FROM Customers CROSS JOIN Movies INNER JOIN: SELECT Movies.CustomerID, Movies.Movie, Customers.Age, Customers.Gender, Customers.[Education Level], Customers.[Internet Connection], Customers.[Marital Status] FROM Customers INNER JOIN Movies ON Customers.CustomerID

问题 I tried using Cross Join but it takes 5 minutes to run, there is another way to do that? Note: I'm comparing dates and Int Fields, Table 1 has records from a system and table 2 store a work calendar dates. SQL Server. B FILE C FILE Trying to achieve SampleCode 回答1: You don't make it easy, but here is a working solution. In the future try to use this type of code in your question so we can focus on the query and solution. I have edited some of your dates to make the example work. EDIT : New

问题 I have a set of data that shows users, collections of fruit they like, and home city: Alice\tApple:Orange\tSacramento Bob\tApple\tSan Diego Charlie\tApple:Pineapple\tSacramento I would like to create a pig query that correlates the number of users that enjoy tyeps of fruits in different cities, where the results from the query for the data above would look like this: Apple\tSacramento\t2 Apple\tSan Diego\t1 Orange\tSacramento\t1 Pineapple\tSacramento\t1 The part I can't figure out is how to

问题 Can someone please help in converting the following sql to linq in c#? select s.SYSTEM_NAME, r.RESET_CODE, COUNT(v.reset_code) from (select distinct system_name from tbl) s cross join (select distinct reset_code from tbl) r left join tbl v on v.SYSTEM_NAME = s.SYSTEM_NAME and v.RESET_CODE=r.RESET_CODE group by s.SYSTEM_NAME,r.RESET_CODE 回答1: Cross joins are generally represented as multiple from clauses in a query expression, or a call to SelectMany in extension method syntax. So the first

问题 This question is a spin-off of RavenDB: Why do I get null-values for fields in this multi-map/reduce index?, but I realized, the problem was another. Consider my extremely simplified domain, rewritten to a movie rental store scenario for abstraction: public class User { public string Id { get; set; } } public class Movie { public string Id { get; set; } } public class MovieRental { public string Id { get; set; } public string MovieId { get; set; } public string UserId { get; set; } } It's a

问题 For some reason the data condition in the where clause is being ignored - any suggestions? SELECT D.[Date], D.Year, D.MonthName, D.WeekOfYear, E.bu_name, E.emp_mgr, E.emp_sup, E.emp_name, E.emp_jde, C.calls, s.sales FROM DateTable AS D CROSS JOIN EmployeeTable AS E LEFT JOIN (SELECT CAST([start_date] AS DATE) AS call_date, [agent_no] AS agent_id, SUM(CASE WHEN [skill_name] LIKE '5700 Sales l%' AND [Agent_Time] != '0' THEN 1 ELSE 0 END) AS calls FROM CallTable GROUP BY CAST([start_date] AS

问题 I'm a little confused on when to use both of these operators. I feel like I understand them but I have a hard time figuring out when I would need them in a relational algebraic statement. Can someone give me some insight/advice on this? 回答1: Some versions of the relational algebra have relation headings that are sets of (unordered, uniquely named) attributes. Then (relational (Cartesian)) PRODUCT, aka CROSS JOIN, aka CROSS PRODUCT, is defined only when the input relations share no attribute

问题 We have a table with one Measure [Discount Amount] on the COLUMNS and CROSSJOIN of [Product].[Product Categories] and [Geography].[Geography] on ROWS axis. We use ORDER function to sort entities by [Discount Amount] with option "BDESC". MDX: SELECT NON EMPTY {[Measures].[Discount Amount]} ON COLUMNS ,NON EMPTY Order ( { Hierarchize ( { CrossJoin ( { Hierarchize ( { [Product].[Product Categories].[All Products] ,[Product].[Product Categories].[All Products].Children } ) } ,{Hierarchize({