Nested select

<div class="Section1"><p class="MsoNormal"><font face="Arial" size="2"><span lang="DE-CH" style="font-size:
10.0pt;font-family:Arial">Hi,</span></font><p class="MsoNormal"><font face="Arial" size="2"><span lang="DE-CH"
style="font-size:
10.0pt;font-family:Arial"> </span></font><p class="MsoNormal"><font face="Arial" size="2"><span lang="EN-GB"
style="font-size:
10.0pt;font-family:Arial">I am migrating my application from MySQL to Postgresql and have met following
situation:</span></font><pclass="MsoNormal"><font face="Arial" size="2"><span lang="EN-GB" style="font-size: 
10.0pt;font-family:Arial"> </span></font><p class="MsoNormal"><font face="Arial" size="2"><span lang="EN-GB"
style="font-size:
10.0pt;font-family:Arial">SELECT</span></font><p class="MsoNormal"><font face="Arial" size="2"><span lang="EN-GB"
style="font-size:
10.0pt;font-family:Arial">(sum(sold_price)/(select sum(sold_price) from car_archive))*100 as CA_pcent,</span></font><p
class="MsoNormal"><fontface="Arial" size="2"><span lang="EN-GB" style="font-size: 
10.0pt;font-family:Arial">reason_text</span></font><p class="MsoNormal"><font face="Arial" size="2"><span lang="EN-GB"
style="font-size:
10.0pt;font-family:Arial">FROM car_archive</span></font><p class="MsoNormal"><font face="Arial" size="2"><span
lang="EN-GB"style="font-size: 
10.0pt;font-family:Arial">group by reason_text</span></font><p class="MsoNormal"><font face="Arial" size="2"><span
lang="EN-GB"style="font-size: 
10.0pt;font-family:Arial">order by CA_pcent desc</span></font><p class="MsoNormal"><font face="Arial" size="2"><span
lang="EN-GB"style="font-size: 
10.0pt;font-family:Arial"> </span></font><p class="MsoNormal"><font face="Arial" size="2"><span lang="EN-GB"
style="font-size:
10.0pt;font-family:Arial">works perfectly in MySQL, but not in Postgresql. The problem seems to be the nested select
whichshould deliver a sum of the whole table, but it does not.</span></font><p class="MsoNormal"><font face="Arial"
size="2"><spanlang="EN-GB" style="font-size: 
10.0pt;font-family:Arial"> </span></font><p class="MsoNormal"><font face="Arial" size="2"><span lang="EN-GB"
style="font-size:
10.0pt;font-family:Arial">If I replace this nested select with a fix value, then it works:</span></font><p
class="MsoNormal"><fontface="Arial" size="2"><span lang="EN-GB" style="font-size: 
10.0pt;font-family:Arial"> </span></font><p class="MsoNormal"><font face="Arial" size="2"><span lang="EN-GB"
style="font-size:
10.0pt;font-family:Arial">SELECT</span></font><p class="MsoNormal"><font face="Arial" size="2"><span lang="EN-GB"
style="font-size:
10.0pt;font-family:Arial">(sum(sold_price)/(333))*100 as CA_pcent,</span></font><p class="MsoNormal"><font face="Arial"
size="2"><spanlang="EN-GB" style="font-size: 
10.0pt;font-family:Arial">reason_text</span></font><p class="MsoNormal"><font face="Arial" size="2"><span lang="EN-GB"
style="font-size:
10.0pt;font-family:Arial">FROM car_archive</span></font><p class="MsoNormal"><font face="Arial" size="2"><span
lang="EN-GB"style="font-size: 
10.0pt;font-family:Arial">group by reason_text</span></font><p class="MsoNormal"><font face="Arial" size="2"><span
lang="EN-GB"style="font-size: 
10.0pt;font-family:Arial">order by CA_pcent desc</span></font><p class="MsoNormal"><font face="Arial" size="2"><span
lang="EN-GB"style="font-size: 
10.0pt;font-family:Arial"> </span></font><p class="MsoNormal"><font face="Arial" size="2"><span lang="EN-GB"
style="font-size:
10.0pt;font-family:Arial">Has someone a solution for that situation?</span></font><p class="MsoNormal"><font
face="Arial"size="2"><span lang="EN-GB" style="font-size: 
10.0pt;font-family:Arial"> </span></font><p class="MsoNormal"><font face="Arial" size="2"><span lang="EN-GB"
style="font-size:
10.0pt;font-family:Arial">Thanks,</span></font><p class="MsoNormal"><font face="Arial" size="2"><span lang="EN-GB"
style="font-size:
10.0pt;font-family:Arial">Hubert Retif</span></font></div>