I'm trying to create a validation rule in order to get an error message if at least one of my all picklists' is blank. I tried to create it with AND() connector instead of the fact that this connector only support two conditions :
 

AND(AND(AND(ISPICKVAL( Visite_Effectu_e__c ,"Oui"),ISBLANK( Dur_e_Visite_Minutes__c )),ISBLANK( Interlocuteur_Pr_nom_Nom_1_del__c)),AND(AND(ISPICKVAL(Fonction_1__c ,""),ISPICKVAL( Pr_sence_d_un_rayon_libre_acc_s__c,"")),ISPICKVAL( Pr_sence_borne_anti_vol__c ,"")))

The logic behind this formula is :
 

AND ( AND ( AND (A,B) , C ), AND ( AND (D,E) , F ) )

If one of A, B, C, D, E or F picklists' is blank, you can't end the report and get an error.

If it's not clear, i can re-explain my problem or my formula ! 

Thank you for your help ! 
 

I'm trying to create a validation rule in order to get an error message if at least one of my all picklists' is blank. I tried to create it with AND() connector instead of the fact that this connector only support two conditions :
 

AND(AND(AND(ISPICKVAL( Visite_Effectu_e__c ,"Oui"),ISBLANK( Dur_e_Visite_Minutes__c )),ISBLANK( Interlocuteur_Pr_nom_Nom_1_del__c)),AND(AND(ISPICKVAL(Fonction_1__c ,""),ISPICKVAL( Pr_sence_d_un_rayon_libre_acc_s__c,"")),ISPICKVAL( Pr_sence_borne_anti_vol__c ,"")))

The logic behind this formula is :
 

AND ( AND ( AND (A,B) , C ), AND ( AND (D,E) , F ) )

If one of A, B, C, D, E or F picklists' is blank, you can't end the report and get an error.

If it's not clear, i can re-explain my problem or my formula ! 

Thank you for your help !