Question

I have a 5 column table (columns are id , answer, weight, quiz_id and question_id)
and I would like to sort it by question_id, then sort by weihgt, then I would like to renumber the id column incrementally according to this double sorting.
Is it possible in mysql (I am using phpmyadmin)?

thanks

something like:

SELECT 
   @curRow := @curRow + 1 AS id,
   T.Answer, T.Weight, T.Quiz_Id, T.Question_Id
FROM wp_wpss_Answers T
   JOIN    (SELECT @curRow := 0) r
ORDER BY QuestioN_Id, Weight
LIMIT 0 , 1000

Answer 1

Assuming you just want to show the row number with your query, then use something like this:

SELECT 
   @curRow := @curRow + 1 AS RowNumber,
   T.Answer, T.Weight, T.Quiz_Id, T.Question_Id, T.Id
FROM YourTable T
   JOIN    (SELECT @curRow := 0) r
ORDER BY QuestioN_Id, Weight

If you’re wanting to update your ID, you can use the above, but I’d ask why are you doing this? I can’t see any reason to renumber your ID columns — set it to an Identity and let MySQL handle it.

However, to update your Id column, try something like this:

UPDATE YourTable t
  JOIN (SELECT 
       @curRow := @curRow + 1 AS RowNumber,
       T.Answer, T.Weight, T.Quiz_Id, T.Question_Id, T.Id
    FROM YourTable T
       JOIN    (SELECT @curRow := 0) r
    ORDER BY QuestioN_Id, Weight) T2 ON T.Id = T2.Id
SET t.Id = T2.RowNumber

And here is the Fiddle.

But you really should reconsider this approach.

Good luck.