Comments on: MySQL’s Funny Math

By: Leif

Leif — Wed, 12 Apr 2006 14:50:53 +0000

I don’t think ’select 11/5;’ should be considered Integer math and yes, I would expect 2.2. Yes, 11 and 5 are integers but that doesn’t mean anything, even floats are integers sometimes. Now, if you typed ’select `col_a` / `col_b`;’ and both col_a and col_b were integer types then sure, the result should be 2. Likewise if one uses a function which is defined as being an integer function then I would expect an integer.

The round behavior is odd though, I would expect a default of rounding to the nearest with an option to specify round up/down if preffered.

By: joseph

joseph — Fri, 24 Mar 2006 06:00:19 +0000

George – I’m going to leave the comment, I think the additional reference to rounding methods is worthwhile.

By: George

George — Fri, 24 Mar 2006 05:23:23 +0000

just a quick note re MySQL’s rounding: it’s not wrong at all; MySQL uses the perfectly valid ’round to even’ method of rounding. For more info: http://en.wikipedia.org/wiki/Rounding

By: imran

imran — Fri, 04 Nov 2005 19:02:00 +0000

I am in big problem since many days. Any kind of help would be appeiciated.

I want some help to enter data into mysql databasefrom a flash form using coldfusion components ?

i’m using web services and simply want to pass data from my flash form to my cfc while staying in flash…

any actionscript (or coldfusion code ‘cfc’) that anyone could provide or even links to other ressources on this specific topic would be awesome…

if someone could help me with this process i would be greatful…..

thank you in advance…

Imran Hashmi
http://www.visionstudio.co.uk

By: nullgod

nullgod — Fri, 12 Nov 2004 02:59:47 +0000

In answer to Mark Stosberg’s comment on why its not the expected result is because integer maths normally always return an integer, and if your expecting an integer and get a floating point number problems can occur. If you want a real answer then you use floating point maths. That rounding issue is rather more scary to me…viva la piggy-squeal (pgsql)

By: Karim

Karim — Wed, 10 Nov 2004 07:40:40 +0000

I have got such problems while trying to calculate the varege of a class, ans so I were obliged to do it with PHP code directly, now it seems that after two years I’ve found the answer, I thought that I was a bug, but it’s nothing else an other limit of MySql, postgresql is great anyway !

By: Joseph Scott

Joseph Scott — Wed, 10 Nov 2004 01:44:49 +0000

Really? I tried out bc with 11/5 and got 2. With 11%5 I got 1, just like PostgreSQL did. Again, the MySQL isn’t wrong, for this case, just perhaps not what some would expect. It is also inconsistent with their DIV() function, which I would expect to work the same way as the math operator of the same name.

By: Mark Stosberg

Mark Stosberg — Wed, 10 Nov 2004 01:34:24 +0000

Why are programmers more likely to expect the answer that PostgreSQL gives for division than MySQL? I would expect the MySQL answer myself, because it ‘more accurate’ in the sense that it contains more significant digits. It’s also the answer I get whenn using the ‘bc’ command line calculator. (I’m a programmer who prefers PostgreSQL).