In Table 9.5 the division of 9 by 4 is indeed described clearly. But there is no example of 4/9 and the different ways of formatting it as a decimal fraction with different options for rounding or a percentage. Two or three added examples would make life easier for folks who have not progressed much beyond 8th grade math.
From: "David G. Johnston" <david.g.johns...@gmail.com> Date: Wednesday, March 7, 2018 at 11:43 AM To: Martin Mueller <martinmuel...@northwestern.edu> Cc: "email@example.com" <firstname.lastname@example.org> Subject: Re: a very primitive question about division On Wed, Mar 7, 2018 at 10:30 AM, Martin Mueller <martinmuel...@northwestern.edu<mailto:martinmuel...@northwestern.edu>> wrote: Thanks. So round(before1550/colfreq::numeric, 2) produces the desired result. The explanations and examples of string functions in the Postgres documentation are a model of clarity. The explanations and examples of basic arithmetic operations are not. There is room for improvement there. Possibly. Patches (or even just email suggestions - though the former are generally more apt to get applied) detailing specific improvements to make are welcome. The description "division (integer division truncates the result)" seems reasonably clear - if you don't want the result truncated, and have two integers, you have to make one of the inputs a non-integer. Of the various options I tend to choose numeric though others are possible. David J.