join (4,679)


haskell - What is a monad?

haskell - What is a monad?

Having briefly looked at Haskell recently, what would be a brief, succinct, practical explanation as to what a monad essentially is? I have found most explanations I've come across to be fairly inacc…


How do I use T-SQL Group By

I know I need to have(although I don't know why) a GROUP BY clause on the end of a SQL query that uses any aggregate functions like count, sum, avg, etc: SELECT count(userID), userName FROM users GR…


Multiple foreign keys?

I've got a table that is supposed to track days and costs for shipping product from one vendor to another. We(brilliantly:p) stored both the shipping vendors(FedEx, UPS) with the product handling…


Beginners Guide to LINQ

During the beta of Stack Overflow, I have seen quite a few questions about LINQ SQL but know nothing about it... it sounds very interesting. What is LINQ and how do I get started? Links guides or doc…


SQL Table Aliases-Good or Bad?

What are the pros and cons of using table aliases in SQL? I personally try to avoid them, as I think they make the code less readable(especially when reading through large where/and statements), bu…


sql - Use a LIKE clause in part of an INNER JOIN

Can/Should I use a LIKE criteria as part of an INNER JOIN when building a stored procedure/query? I'm not sure I'm asking the right thing, so let me explain. I'm creating a procedure that is going to…


python - updating an auto_now DateTimeField in a parent model w/ Django

I've got two models: Message and Attachment. Each attachment is attached to a specific message, using a ForeignKey on the Attachment model. Both models have an auto_now DateTimeField called updated.…


c# - Most efficient way to concatenate strings?

What's the most efficient way to concatenate strings?…



sql - Represent Ordering in a Relational Database

I have a collection of objects in a database. Images in a photo gallery, products in a catalog, chapters in a book, etc. Each object is represented as a row. I want to be able to arbitrarily order…


sql server - Good way to use table alias in Update statement?

I'm using SQL Server, and trying to update rows from within the same table. I want to use a table alias for readability. This is the way I am doing it at the moment: UPDATE ra SET ra.ItemValue=rb.It…




multiple query sql with example tables select how from table