ケースエラー今関数を宣言しながら（SQLサーバ）以下のように補正

Question

create function whichcountry(@city varchar(20)) returns varchar(30) 
as 
begin 
declare @return varchar(30) 
select @return = 
    CASE @city 
when 'New delhi' then 'India' 
when 'Mumbai' then 'India' 
when 'Dhaka' then 'Bangladesh' 
else 'UNKNOWN' 
end 
return @return 
end 

select country = dbo.whichcountry(city.city),city *from city 
create table city(eno int, 
        ename varchar(20), 
        city varchar(30)); 

insert into city values(1,'Ray','New Delhi'), 
         (2,'Jash','Mumbai'), 
         (3,'Ravi','Dhaka'); 

Answer 1

から*にエラーが発生した

create function whichcountry(@city varchar(20)) returns varchar(30) 
as 
begin 
declare @return varchar(30) 
select @return = 
    CASE @city 
when 'New delhi' then 'India' 
when 'Mumbai' then 'India' 
when 'Dhaka' then 'Bangladesh' 
else 'UNKNOWN' 
end 
return @return 
end 

修正：

CASE @city値を@return変数

に割り当てられていませんでした