I'm ashamed of myself 'cause i can't do this query properly... I have a table like this
nom | code_geo | valeur | indice
-------+----------+--------+--------------------
AISNE | 02 | 81573 | 0.05
SOMME | 80 | 79520 | 0.03
OISE | 60 | 70004 | 0.09
what i need to do is divide each "indice" by the max(indice). That is:
nom | code_geo | valeur | indice
-------+----------+--------+--------------------
AISNE | 02 | 81573 | 0.05 / 0.09
SOMME | 80 | 79520 | 0.03 / 0.09
OISE | 60 | 70004 | 0.09 / 0.09
my first gue开发者_StackOverflow社区ss is:
SELECT nom,code_geo,valeur,indice/(SELECT max(indice) FROM blablabla) FROM blablabla;
my problem is that "blablabla" is actually a function with 6 parameter and i don't want to repeat the FROM clause on the subquery...
Is there another (better?) way to do this? or should i look the other way
Thx in advance
You solution looks fine. Since the subquery is not correlated to the outer query, the DBMS should evaluate that subquery only once.
I believe Postgresql allows CTE.
Select * into yourtable from blablabla
WITH T2(MaxNumber) as
(
select MAX(indice) as MaxNumber from yourtable
)
update t1
set t1.indice=t1.indice / T2.MaxNumber
from yourtable t1, T2
精彩评论