在 mysql 中使用 CASE 函数但得到错误代码时出现问题:1241。操作数应包含 1 列

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

我在 mysql 的函数中使用 CASE 语句,如下所示:

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);

但我每次都遇到这个错误。 请帮忙

似乎你在 WHEN 条件中有错误的 ()
尝试

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