bonjour je suis nouveau sur le forum et merci pour les gens qui vont me répondre  
 
voila j'ai fais cette requête en mysql et elle me renvoi pas de résultat :

 
j'aimerai savoir si il ya une erreur dans la syntaxe (quand j’exécute chaque requête séparément ça marche )
 
merci d'avance

On met pas d'alias dans un group by
 
 

 
 
Et on indente une requete
 
 

bonjour j'ai réussi à la réaliser avec case when  :
 
select DAYNAME(str_to_date(datevisite, '%d/%m/%y')) as jour,m.designation ,
case DAYNAME(str_to_date(datevisite, '%d/%m/%y')) when 'Monday' then count(*)/(select count(*) from ( SELECT distinct DAYNAME(str_to_date(datevisite, '%d/%m/%y')) as nomjour,
str_to_date(datevisite, '%d/%m/%y')as ladate from identimotif idm,identification idf,motif m where
idf.idclient=idm.idclient and m.idmotif= idm.idmotif and DAYNAME(str_to_date(datevisite, '%d/%m/%y'))='Monday' and
 str_to_date(datevisite, '%d/%m/%y %T')  between
 str_to_date('20/03/12 08:30:00', '%d/%m/%y %T') and  str_to_date('06/07/12 16:30:00', '%d/%m/%y %T')) as res
group by nomjour) when 'Friday' then count(*)/(select count(*) from ( SELECT distinct DAYNAME(str_to_date(datevisite, '%d/%m/%y')) as nomjour,
str_to_date(datevisite, '%d/%m/%y')as ladate from identimotif idm,identification idf,motif m where
idf.idclient=idm.idclient and m.idmotif= idm.idmotif and DAYNAME(str_to_date(datevisite, '%d/%m/%y'))='Friday' and
 str_to_date(datevisite, '%d/%m/%y %T')  between
 str_to_date('20/03/12 08:30:00', '%d/%m/%y %T') and  str_to_date('06/07/12 16:30:00', '%d/%m/%y %T')) as res
group by nomjour)
when 'Tuesday' then count(*)/(select count(*) from ( SELECT distinct DAYNAME(str_to_date(datevisite, '%d/%m/%y')) as nomjour,
str_to_date(datevisite, '%d/%m/%y')as ladate from identimotif idm,identification idf,motif m where
idf.idclient=idm.idclient and m.idmotif= idm.idmotif and DAYNAME(str_to_date(datevisite, '%d/%m/%y'))='Tuesday' and
 str_to_date(datevisite, '%d/%m/%y %T')  between
 str_to_date('20/03/12 08:30:00', '%d/%m/%y %T') and  str_to_date('06/07/12 16:30:00', '%d/%m/%y %T')) as res
group by nomjour) when 'Wednesday' then count(*)/(select count(*) from ( SELECT distinct DAYNAME(str_to_date(datevisite, '%d/%m/%y')) as nomjour,
str_to_date(datevisite, '%d/%m/%y')as ladate from identimotif idm,identification idf,motif m where
idf.idclient=idm.idclient and m.idmotif= idm.idmotif and DAYNAME(str_to_date(datevisite, '%d/%m/%y'))='Wednesday' and
 str_to_date(datevisite, '%d/%m/%y %T')  between
 str_to_date('20/03/12 08:30:00', '%d/%m/%y %T') and  str_to_date('06/07/12 16:30:00', '%d/%m/%y %T')) as res
group by nomjour) when 'Thursday' then count(*)/(select count(*) from ( SELECT distinct DAYNAME(str_to_date(datevisite, '%d/%m/%y')) as nomjour,
str_to_date(datevisite, '%d/%m/%y')as ladate from identimotif idm,identification idf,motif m where
idf.idclient=idm.idclient and m.idmotif= idm.idmotif and DAYNAME(str_to_date(datevisite, '%d/%m/%y'))='Thursday' and
 str_to_date(datevisite, '%d/%m/%y %T')  between
 str_to_date('20/03/12 08:30:00', '%d/%m/%y %T') and  str_to_date('06/07/12 16:30:00', '%d/%m/%y %T')) as res
group by nomjour)   end  from identimotif idm,identification idf,motif m where
idf.idclient=idm.idclient and m.idmotif= idm.idmotif and
str_to_date(datevisite, '%d/%m/%y %T') between
str_to_date('20/03/12 08:30:00', '%d/%m/%y %T') and str_to_date('06/07/12 16:30:00', '%d/%m/%y %T')
group by DAYNAME(str_to_date(datevisite, '%d/%m/%y')),m.designation

lol
Faut revoir le formatage en premier si tu veux que quelqu'un t'aide.
 
Sinon a vue de nez il y a moyen de faire ca en beaucoup plus court et lisible en utilisant des JOIN et different group by.
 
Et surtout, eviter les subselect dans le case, ca va plomber les perfs d'une maniere extraordinaire.