Unable to return a number from CASE statement in plsql

Question

Hello all!
Back in November of last year, I received some assistance from user "jarola" regarding changing the color of a column item in a query based on the resulting value. This discussion yielded;
declare
   l_query varchar2(4000) := '';
begin
   l_query := '
     select i.INVENTORY_ID,
            io.ORDER_QUANTITY,
            CASE
               WHEN i.QUANTITY_AVAILABLE=0
               THEN ''<span style="color:red;"> ''|| i.QUANTITY_AVAILABLE ||''</span>''
               ELSE to_char(i.QUANTITY_AVAILABLE)
            END,
            i.QUANTITY_AVAILABLE qty_avail_hold,
            i.STRAIN_CODE,
            i.STRAIN_NAME,
            i.GENOTYPE,
            i.AGE,
            i.***,
            (lower(substr(i.ROOM_NUMBER,1,instr(i.ROOM_NUMBER,''-'',1,1)-1))) ROOM_NUMBER
     from   SM_INVENTORY i,
            SM_INVENTORY_ORDER io
     where  io.ORDER_ID (+)= :F111_MODIFYING_ORDER
     and    io.INVENTORY_ID (+)= i.INVENTORY_ID';
return l_query;
end;Problem is, sorting (report attributes for column set to "sort") on column i.QUANTITY_AVAILABLE is broken as even though the data in the table is number(12,0), the CASE statement returns it as alpha. I'm having difficulty getting this CASE statement to return a number as these modifications cause generic compilation errors.
ELSE i.QUANTITY_AVAILABLE
ELSE to_number(i.QUANTITY_AVAILABLE)
Google/sqlplus docs have yielded little. Might anyone offer advice?
Thanks!!!
Paul

Answer 1

Hello Varad! Thanks for the reply.
Sorry, but I copied some old information in my code example. the CASE statement I'm actually using is;
CASE
   WHEN i.QUANTITY_AVAILABLE=0
   THEN ''<span style="color:red;"> ''|| i.QUANTITY_AVAILABLE ||''</span>''
   ELSE to_char(i.QUANTITY_AVAILABLE)
   END AS QUANTITY_AVAILABLESo I'm already returning the result as labeled "QUANTITY_AVAILABLE".
What I did was click on the pencil/paper icon to the left of the alias of my column in the "Column Attributes" pane in "Report Attributes" to get to the "Column Attributes" page and plugged #QUANTITY_AVAILABLE# into the HTML Expression field of the "Column Formatting" pane of the "Column Attributes" page for the "QUANTITY_AVAILABLE" column.
No joy, sort still broken...
Isn't the problem that fundamentally, the CASE statement returns an alpha? I wouldn't expect the sort to ever work until it can return a number (which it appears SQL, used this way, it cannot do).
So, I considered that END AS QUANTITY_AVAILABLE might be the problem as it's named the same as the column, so I changed it (and the HTML Expression entry) to END AS QUANTITY_AVAIL (changed the name).
Sort as alpha still happening.
Any other thoughts?