Tips for Simplifying Crosstab Query Statements
After the All About the Crosstab Query article was published,MBT Baridi Schuhe, some astute readers pointed out that my SQL statement was more complex than it needed to be. Their suggestions sent me in search of a simplified statement that would yield the same results. There were a couple of ways to shorten and simplify the SQL ?in some cases, substantially. We will be reviewing the most effective solutions today, which include using the CASE statement within the Count() function and the specialized WITH ROLLUP GROUP BY Modifier.
The CASE Statement
The CASE statement is a type of conditional construct much like an IF ELSE. It evaluates a search condition and executes the corresponding SQL statement list, depending on which condition evaluates to true. If no search condition matches,Mbt Nafasi Mid Schuhe schwarz WoMänner, the statement list in the ELSE clause is executed instead. Each statement list may consist of one or more statements. Multiple statements are enclosed between the BEGIN and END
I often find discussions about whether SPARQL is difficult to be a bit silly. Not that SPARQL is incredibly easylthough I do find it easy enough as query or scripting languages gout because any talk of its suitability for your Mom is just a red herring. In a January blog posting titled Hey CNN,Christian Louboutin chaussures Daffodile 160mmLivraison gratuite pour vous, SPARQL isn't so difficult,Neue MBT Schuhe Herren Nafasi Myrup, I wrote that as with SQL and other query languages,Christian Louboutin Maggie 140mm de sortievente au rabais, no one expects end users to type out SPARQL queries,read more, but that someone who already knows a scripting language or two can pick up SPARQL and use it to build new kinds of applications.
I've written an article titled Build Wikipedia query forms with semantic technology to demonstrate how,Mbt Fanaka GTX Schuhe offwhite, and it's now live on IBM's developerWorks website. The article walks the reader through the components of two simple form-driven applications: one that queries the Internet Movie Database for the names of actors who have appeared in movies by the two directors whose names you enter on the input form (for example,Hogan Uomo Interactive Nero Bianco, only Kathleen Turner has appeared in both a Francis Ford Coppola film and a Sofia Coppola film), and another that retrieves nicely-formatted information about recording artist albums from DBpedia.
I tried to make it clear in the article that the cool part of all this is not this relatively new query language,Mbt Schuhe DaMänner Kamba Schokolade, but the existence of these collections of data that can be accessed by a standard query language and the ease with which one can build a query around search terms entered on a form, then send the query off to the server,Hogan Donna Scarpe Interactive Beige Sconto grande vendita, and then format and display the results in a web pageust as people have done with SQL queries for years now.
I hope I got those points across, and that the article helps more people understand the contributions that SPARQL and linked data can make to useful applications that couldn't exist otherwise.相关的主题文章：
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