Re: SQL that performs division
- From: Lew <lew@xxxxxxxxxxxxxxxxxxxx>
- Date: Sun, 25 Feb 2007 10:48:22 -0500
Chris wrote:
I have a table that has some measures for recipes. Things like cup
pint gallon etc... I am trying to write something that can convert
between them easily. So far this is the direction i have taken:
I have a database that has, among other data:
Teaspoon 1
Tablespoon 3
Fluid OZ 6
Gill 24
Cup 48
Pint 96
Quart 192
Gallon 768
Firkin 6912
Hogshead 48384
That is a list of some of the values, it is column measure_name and
conversion_rate, the conversion rate for these measures are all
exressed in teaspoons.
The SQL query I wrote to do the conversion is here:
-- how many cups in a hogshead?
SELECT b1/a1 conversion FROM
(SELECT m.conversion_rate a1 FROM measure m
WHERE m.measure_name = 'cup') a, (SELECT m1.conversion_rate b1 FROM
measure m1
WHERE m1.measure_name = 'hogshead') b;
I'm using MySQL 5.0, im sure there are functions i can be using but
the join is what im worried about the most,
This to me is a very ugly SQL query and im thinking there's a better
way to do this, does anyone have any ideas on how i can improve this
query?
Consider using a front-end language like Java, C#, Basic, FORTRAN, Perl or whatever to interact with the database. Let the database handle data. Let the logic layer handle logic.
- Lew
.
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