Skip to main content

SQL Workshop - Selecting columns without including a non-aggregate column in the group by clause

Thinking in terms of sets and set operations can be difficult at first but after a while you discover that you can do things without needed to drop down to procedural approaches.

This scenario requires us to be members of a hospital's Dietary Department and with the end of the year approaching we are assigned the task of estimating the amount of money needed for next year’s resource shopping, to keep the patients fed for the coming twelve months.

So we need to find the sum of the mean amount spent on the resources/raw material (vegetables, fruit, meat etc) grouped by Account Category (i.e. the account that serves for fruit) and Account Id (actual account number) used for their shopping, and use that as the basis for our new season’s budget estimate.

When a request for, say, fruit comes in, we translate that request into the amount of money consumed using a formula based on the fruit’s dynamically updated Mean Value, the Quantity of the request and a Ratio.

When the unit of measurement is 'PIECES' then our formula is :
Amount = Mean Value x Quantity x Ratio

while when the unit of measurement is a ‘KGR’ then the formula becomes:
Amount = Mean Value x Quantity / Ratio

The nature and meaning of the two formulae isn't as important as the fact that they vary according to the value of the Unit field.


Read full article on i-programmer

Comments

Popular posts from this blog

Book Review : How To Create Pragmatic, Lightweight Languages

At last, a guide that makes creating a language with its associated baggage of lexers, parsers and compilers, accessible to mere mortals, rather to a group of a few hardcore eclectics as it stood until now.

The first thing that catches the eye, is the subtitle:

The unix philosophy applied to language design, for GPLs and DSLs"
What is meant by "unix philosophy" ?. It's taking simple, high quality components and combining them together in smart ways to obtain a complex result; the exact approach the book adopts.
I'm getting ahead here, but a first sample of this philosophy becomes apparent at the beginnings of Chapter 5 where the Parser treats and calls the Lexer like  unix's pipes as in lexer|parser. Until the end of the book, this pipeline is going to become larger, like a chain, due to the amount of components that end up interacting together.

The book opens by putting things into perspective in Chapter 1: Motivation: why do you want to build lan…

How Much Gameplay Can You Pack In Just 13K?

Given our expectations of Xbox games, you might consider writing a game within a 13K limit, which is the challenge for the annual js13K competition far too restrictive. Its results are now out and prove that it is possible to produce a game that is fun to play. 

Back in the tape loading days and on platforms the likes of Commodore64 games came in sizes of 4K or less. As proof of concept, here's a list of a few such 4K titles, copied over from Lemon64 's archive:
Alien SidestepBug CrusherDot GobblerClose EncountersDot Gobbler v2GridrunnerLaser CyclesMarios BrewerySpace ActionSpace RicoshayTank WarsHesmon64Retro Ball  Fast forward to now, at a time when Javascript's eating the world by making all sorts of applications or  games available to everyone through the medium of the browser, rendering the need of dedicated platforms and Operating systems obsolete, 13K is sufficient enough to pack both gameplay AND cool graphics due to the advanced browser engines and HTML5.

Hour of Code 2017 Introduces App Lab

t's the time of year when the world-class Hour of Code once more commences; just an hour for introducing coding to the uninitiated, having them complete self guided tutorials. But is a hour sufficient? What can a beginner actually code within this limit? The answer is a bit more complicated than that, so let's find out all about it! Integrated into the larger, worldwide, annual Computer Science Education week, this year taking place December 4-10, Hour of Code's novel mission has always been to get everybody coding, aged from 4 to 104, by providing: "a one-hour introduction to computer science, designed to demystify code, showing that anybody can learn the basics, and broadening participation in the field of computer science". But first of all, why this obsession with Computer Science, in particular in getting  kids as young as 4 to learn to code? The answer is simple. Nowadays code is everywhere around us, from desktop computers to mobile phones and, thanks to w…