Problem when using CASE function in mysql but getting Error Code: 1241. Operand should contain 1 column(s)

Question

I am using CASE statement in a function in mysql like this:

BEGIN
declare Rslt1 decimal(10,2);declare Rslt2 int;declare Rslt3 int;
declare Rslt decimal(10,2);declare Tot decimal(10,2);
set Tot = UnitPrice * OrderQty;
if Calctype = 0 then
 set Rslt1 = Tot;
elseif CalcType=1 then -- Buy X Pay Y
 set Rslt2 = floor((OrderQty/X));
 set Rslt3 = (Orderqty - (RSlt2 * X));
 set Rslt1 = CASE
    WHEN Rslt2 =0 THEN  Tot
    WHEN Rslt2>=1 THEN amntpercent(((Rslt2 * UnitPrice * X),ByAmnt, Dscnt) + (Rslt3 * UnitPrice))
  End;
elseif CalcType = 2 then -- for X Pay Y ( Discount by Amnount or Percentage)
  set RSlt1= amntpercent(Tot,ByAmny,Dscnt);
end if; 

RETURN (Rslt1);

but I am getting this error every time. Any help please

Answer 1

seems you have wrong () in a WHEN condition
try

WHEN Rslt2>=1 THEN amntpercent((Rslt2 * UnitPrice * X),ByAmnt, Dscnt) + (Rslt3 * UnitPrice)