IIF is the same as CASE WHEN <Condition> THEN <true part> ELSE <false part> END. The query plan will be the same. It is, perhaps, “syntactical sugar” as initially implemented. CASE is portable across all SQL platforms whereas IIF is SQL SERVER 2012+ specific.
Sometimes it is helpful to have multiple cases associated with the same code block, such as case ‘A’: case ‘B’: case ‘C’: doSomething(); break; case ‘D’: case ‘E’: doSomethingElse(); break; etc. Just an example. In my experience, usually it is bad style to “fall through” and have multiple blocks of code execute for one case, … Read more
The case statement uses globs, not regexes, and insists on exact matches. So the empty string is written, as usual, as “” or ”: case “$command” in “”) do_empty ;; something) do_something ;; prefix*) do_prefix ;; *) do_other ;; esac
case_when(), which was added to dplyr in May 2016, solves this problem in a manner similar to memisc::cases(). As of dplyr 0.7.0, for example: mtcars %>% mutate(category = case_when( cyl == 4 & disp < median(disp) ~ “4 cylinders, small displacement”, cyl == 8 & disp > median(disp) ~ “8 cylinders, large displacement”, TRUE ~ … Read more
flatcase or mumblecase kebab-case. Also called caterpillar-case, dash-case, hyphen-case, lisp-case, spinal-case and css-case camelCase PascalCase or CapitalCamelCase snake_case or c_case MACRO_CASE, UPPER_CASE or SCREAM_CASE COBOL-CASE or TRAIN-CASE
You can’t use a condition to change the structure of your query, just the data involved. You could do this: update table set columnx = (case when condition then 25 else columnx end), columny = (case when condition then columny else 25 end) This is semantically the same, but just bear in mind that both … Read more
From a technical standpoint, all three versions are equivalent. That being said, my rule of thumb for styles is that if you can read it as if it was English (read | as “when”, | otherwise as “otherwise” and = as “is” or “be”), you’re probably doing something right. if..then..else is for when you have … Read more
First off, the CASE statement must be part of the expression, not the expression itself. In other words, you can have: WHERE co.DTEntered = CASE WHEN LEN(‘blah’) = 0 THEN co.DTEntered ELSE ‘2011-01-01′ END But it won’t work the way you have written them eg: WHERE CASE LEN(‘TestPerson’) WHEN 0 THEN co.personentered = co.personentered ELSE … Read more
The MSDN is a good reference for these type of questions regarding syntax and usage. This is from the Transact SQL Reference – CASE page. http://msdn.microsoft.com/en-us/library/ms181765.aspx USE AdventureWorks2012; GO SELECT ProductNumber, Name, “Price Range” = CASE WHEN ListPrice = 0 THEN ‘Mfg item – not for resale’ WHEN ListPrice < 50 THEN ‘Under $50’ WHEN … Read more
With System.Web.Routing 4.5 you may implement this straightforward by setting LowercaseUrls property of RouteCollection: public static void RegisterRoutes(RouteCollection routes) { routes.IgnoreRoute(“{resource}.axd/{*pathInfo}”); routes.LowercaseUrls = true; routes.MapRoute( name: “Default”, url: “{controller}/{action}/{id}”, defaults: new { controller = “Home”, action = “Index”, id = UrlParameter.Optional } ); } Also assuming you are doing this for SEO reasons you want … Read more