Please help us help you and fill where relevant:
Your LimeSurvey version: [see right hand bottom of your LimeSurvey admin screen]
Own server or LimeSurvey hosting:
Survey theme/template:
==================
Hi everyone, 
I would like to program 2 questions in LS (for a survey):
1) the first question is a rank (users have to select their preferred options among a list and then rank these options). Minimum one answer, not mandatory
2) the second question is also a rank (users have to select their least preferred options among the same list that was shown in the previous question and rank them). Minimun one answer, not mandatory

My problem is that the answers' options of the second question are those that have not been selected in the first question. How can I do to make appear in Q2 the answers options that have NOT been selected in Q1?

Example:

Q1: Select and rank your preferred brands:
     SQ001: option1
     SQ002: option2 --> this is one of the option selected and ranked as 1st
     SQ003: option3 --> this is one of the option selected and ranked as 2nd
     SQ004: option4
     SQ005: option5
     SQ006: option6

Q2: Select and rank your least favorite:
     SQ001: option1
     SQ002: option2 --> this option is NOT appearing anymore since was already selected as preferred in Q1
     SQ003: option3 --> this option is NOT appearing anymore since was already selected as preferred in Q1
     SQ004: option4
     SQ005: option5
     SQ006: option6     

Thanks!

Hi,
why didn't you answer the questions at the top?

And you did not provide a lss export of a small prototype.
So I only tell you, what you can do.

Between the two questions create 
a question of type "equation"
a question of type "multiple" (M1) with the same subquestion codes as your rankings answer options
Both are hidden.

Here: All subquestion and answer option codes are numerical (1,2,3,...)
In the equation you preset the multiple question, like
{M1_1=if(Q1_1==1 or Q1_2==1,'','Y')}
{M1_2=if(Q1_1==2 or Q1_2==2,'','Y')}
...

Now you can use this multiple question as array filter for your second ranking question.




Joffm