Can you split/explode a field in a MySQL query?

Question

I have to create a report on some student completions. The students each belong to one client. Here are the tables (simplified for this question).

CREATE TAB         


        

Answer 1

I used the above logic but modified it slightly. My input is of format : "apple:100|pinapple:200|orange:300" stored in a variable @updtAdvanceKeyVal

Here is the function block :

set @res = "";

set @i = 1;
set @updtAdvanceKeyVal = updtAdvanceKeyVal;

REPEAT


 -- set r =  replace(SUBSTRING(SUBSTRING_INDEX(@updtAdvanceKeyVal, "|", @i),
 --  LENGTH(SUBSTRING_INDEX(@updtAdvanceKeyVal, "|", @i -1)) + 1),"|","");

-- wrapping the function in "replace" function as above causes to cut off a character from
 -- the 2nd splitted value if the value is more than 3 characters. Writing it in 2 lines causes no such problem and the output is as expected
-- sample output by executing the above function :
-- orange:100
-- pi apple:200    !!!!!!!!strange output!!!!!!!!
-- tomato:500

      set @r =  SUBSTRING(SUBSTRING_INDEX(@updtAdvanceKeyVal, "|", @i),
                  LENGTH(SUBSTRING_INDEX(@updtAdvanceKeyVal, "|", @i -1)) + 1);

      set @r = replace(@r,"|","");

      if @r <> "" then

              set @key = SUBSTRING_INDEX(@r, ":",1);
              set @val = SUBSTRING_INDEX(@r, ":",-1);

              select @key, @val;
      end if;

      set @i = @i + 1;

     until @r = ""
END REPEAT;