Rafael,
Couple of things ... see below. I'm doing this without checking the MySQL
docs, so validate this against them.
At 08:22 PM 5/15/01 -0300, Rafael Faria wrote:
>Hello Guys,
>
>i'm with problems....
>
>first i try to add a value like "8.55" into my sql data base that was set
>up to DOUBLE (10,0) and isn't work... i don't know how this work... but
>i'm here to ask for someone explain me.
Try DOUBLE(10,2), that will provide for the decimal places.
>well... i did with varchar to add this value as i want to..
>
>do i have a lot of values like
>
>
>votes average
> 2 8.5
> 10 5.5
> 1 10
> 20 5.1
>
>
>and i wanna sort by votes and average....
>
>have someway to do that?
Generally, when you store numeric values in a character field, you have to
left pad them with zeroes otherwise you get strange ordering behaviour. If
you want to do arithmetic on these values, don't store them as characters,
store them as one of the numeric types.
If you store numbers as characters, don't waste space with varchar, use a
straight char type.
As for ordering, that is a function of your SELECT statement. Example:
" select * from vote_results order by votes " will order results by an
ascending count of votes.
" select * from vote_results order by votes desc " will order results by a
descending count of votes.
" select * from vote_results order by votes, average " will order results
by an ascending count of votes and then by ascending averages within the
returned set. (I don't know what the point of this would be.)
A comment on your average field. Databases can calculate averages _very_
quickly and it may be better to do that in your SELECT statement. Heres an
extract from the manual:
AVG(expr)
Returns the average value of expr:
mysql> select student_name, AVG(test_score)
from student
GROUP BY student_name;
Hope you find this helpful - Miles Thompson
PS "br" - Brazil? I'm not up on my country codes.
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