错误:PLS-00428:此 select 语句中需要一个 into 子句

I'm trying to create a function as shown below but getting the error stated in the title.

create or replace function gettaxmin(period_tax_type_id in double precision, tax_range in number) return double precision is
  Result double precision;
begin
  SELECT CASE WHEN max(tax_range) is null THEN 0 ELSE max(tax_range) END 

    FROM period_tax_rates WHERE (tax_range < 1) AND (period_tax_type_id = 2);
  return(Result);
end gettaxmin;

有什么想法吗?

推荐答案

您必须将 SELECT 语句的结果存储到一个变量中(在本例中为结果"):

create or replace function gettaxmin
            (period_tax_type_id in double precision, tax_range in number) 
    return double precision 
is
     Result double precision;
begin
  SELECT CASE WHEN max(tax_range) is null THEN 0 ELSE max(tax_range) END 
    INTO Result 
    FROM period_tax_rates WHERE (tax_range < 1) AND (period_tax_type_id = 2);
  return Result;
end gettaxmin;