Oracle自定義聚合函數(shù)實(shí)現(xiàn)字符串連接的聚合

create or replace type string_sum_obj as object (?
--聚合函數(shù)的實(shí)質(zhì)就是一個(gè)對(duì)象?
???? sum_string varchar2(4000),?
???? static function ODCIAggregateInitialize(v_self in out string_sum_obj) return number,?
???? --對(duì)象初始化?
???? member function ODCIAggregateIterate(self in out string_sum_obj, value in varchar2) return number,?
???? --聚合函數(shù)的迭代方法(這是最重要的方法)?
???? member function ODCIAggregateMerge(self in out string_sum_obj, v_next in string_sum_obj) return number,?
???? --當(dāng)查詢語句并行運(yùn)行時(shí),才會(huì)使用該方法,可將多個(gè)并行運(yùn)行的查詢結(jié)果聚合?
??????
???? member function ODCIAggregateTerminate(self in string_sum_obj, return_value out varchar2 ,v_flags in number) return number?
???? --終止聚集函數(shù)的處理,返回聚集函數(shù)處理的結(jié)果.?
)?
/?
create or replace type body string_sum_obj is?
???? static function ODCIAggregateInitialize(v_self in out string_sum_obj) return number is?
???? begin?
???????? v_self := string_sum_obj(null);?
???????? return ODCICONST.Success;?
???? end;?
???? member function ODCIAggregateIterate(self in out string_sum_obj, value in varchar2) return number is?
???? begin?
????????? /* 連接 */????
????????? self.sum_string := self.sum_string || value;?
????????? return ODCICONST.Success;?
????????? /* 最大值 */?
????????? if self.sum_string<value then?
????????????? self.sum_string:=value;?
????????? end if;?
????????? /* 最小值 */?
????????? if self.sum_string>value then?
?????? self.sum_string:=value;???????????
????????? end if;?
???????????
????????? return ODCICONST.Success;?
???? end;?
???? member function ODCIAggregateMerge(self in out string_sum_obj, v_next in string_sum_obj) return number is?
???? begin?
????????? /* 連接 */????
????????? self.sum_string := self.sum_string || v_next.sum_string;?
????????? return ODCICONST.Success;?
????????? /* 最大值 */?
????????? if self.sum_string<v_next.sum_string then?
????????????? self.sum_string:=v_next.sum_string;?
????????? end if;?

????????? /* 最小值 */?
????????? if self.sum_string>v_next.sum_string then?
????????????? self.sum_string:=v_next.sum_string;???????????
????????? end if;?
???????????
????????? return ODCICONST.Success;?
???? end;?
???? member function ODCIAggregateTerminate(self in string_sum_obj, return_value out varchar2 ,v_flags in number) return number is?
???? begin?
????????? return_value:= self.sum_string;?
????????? return ODCICONST.Success;?
???? end;?
end;?
/?
create or replace function ConnStrSum(value Varchar2) return Varchar2?
???? parallel_enable aggregate using string_sum_obj;

轉(zhuǎn)載于:https://www.cnblogs.com/tiandi/p/4821695.html

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