[GitHub] [druid] sascha-coenen edited a comment on issue #9417: SQL: improve division behaviour

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sascha-coenen edited a comment on issue #9417: SQL: improve division behaviour
URL: https://github.com/apache/druid/issues/9417#issuecomment-591918423
 
 
   > Btw, I've never seen a one-arg NVL function.
   
   yeah. missing an arg. alternatively NULLIF(denominator, 0)
   
   > For the 1/NULL case, I think we should probably return NULL instead of throwing an error.
   
   that would be perfect 
   
   > Would adding that function solve your problem?
   
   yes, it would make things more concise.
   I mentioned the function DIV(nominator, denominator, null-fallback) above which is probably similar to their SAFE_DIVIDE function. 
   Having this as an infix operator rather than in function syntax would be even nicer so that there are less nesting levels, but I guess that's out of the question.
   
   Most importantly though, for this to be a perfectly useful function, it would have to divide numerically, meaning DIV(1, 2) should be 0.5 not 0.
   I would argue that user experience trumps technical arguments. So in the real world the expectation of 1 divided by 2 is 0.5 Having equal types is nice from a technical perspective, but to quote Steve Jobs, one should start with the user perspective and work one's way backwards to technology. (https://www.youtube.com/watch?v=r2O5qKZlI50)
   Also why have two different ways to do integer division and none for numerical division, so to even out the scales I would petition for having this DIV() function apply numerical division.
   
   Although it also has to be said that DIV usually represents integer division (https://www.w3schools.com/sql/func_mysql_div.asp) so it would be misleading to have it be a numerical division in Druid, so a different name like SAFE_DIV would be better I think.
   It is sad that databases differ so much on what "/" is doing. Since decimal division is the common case, IT should be the default, especially in the context of having a DIV function for doing the integer division. 
   Paragon of consistency indeed, lol :D

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