在DM 中，可以通过创建自定义的聚集函数来实现PostgreSQL的bit_or聚集函数功能:

首先，需要创建一个类型，该类型定义了一个累加方法（accumulate）和一个合并方法（merge）：

CREATE OR REPLACE TYPE bit_or_agg_type AS OBJECT (
  bit_or_result NUMBER(38),

  STATIC FUNCTION ODCIAggregateInitialize(sctx IN OUT bit_or_agg_type) 
    RETURN NUMBER,

  MEMBER FUNCTION ODCIAggregateIterate(self IN OUT bit_or_agg_type, value IN NUMBER) 
    RETURN NUMBER,

  MEMBER FUNCTION ODCIAggregateTerminate(self IN bit_or_agg_type, returnValue OUT NUMBER, flags IN NUMBER) 
    RETURN NUMBER,

  MEMBER FUNCTION ODCIAggregateMerge(self IN OUT bit_or_agg_type, ctx2 IN bit_or_agg_type) 
    RETURN NUMBER
);

然后，需要为此类型创建一个正文，该正文实现了这些方法：

CREATE OR REPLACE TYPE BODY bit_or_agg_type IS

  STATIC FUNCTION ODCIAggregateInitialize(sctx IN OUT bit_or_agg_type) 
    RETURN NUMBER IS
  BEGIN
    sctx := bit_or_agg_type(NULL);
    RETURN ODCIConst.Success;
  END;

  MEMBER FUNCTION ODCIAggregateIterate(self IN OUT bit_or_agg_type, value IN NUMBER) 
    RETURN NUMBER IS
  BEGIN
    self.bit_or_result := COALESCE(self.bit_or_result, 0) | value;
    RETURN ODCIConst.Success;
  END;

  MEMBER FUNCTION ODCIAggregateTerminate(self IN bit_or_agg_type, returnValue OUT NUMBER, flags IN NUMBER) 
    RETURN NUMBER IS
  BEGIN
    returnValue := self.bit_or_result;
    RETURN ODCIConst.Success;
  END;

  MEMBER FUNCTION ODCIAggregateMerge(self IN OUT bit_or_agg_type, ctx2 IN bit_or_agg_type) 
    RETURN NUMBER IS
  BEGIN
    self.bit_or_result := COALESCE(self.bit_or_result, 0) | COALESCE(ctx2.bit_or_result, 0);
    RETURN ODCIConst.Success;
  END;

END;

最后，创建一个使用该类型的聚集函数：

CREATE OR REPLACE FUNCTION bit_or(input NUMBER) RETURN NUMBER
  PARALLEL_ENABLE AGGREGATE USING bit_or_agg_type;

现在，就可以使用这个bit_or_agg函数来实现PostgreSQL的bit_or聚集函数功能了。例如：

create table bits(
    id int  primary key auto_increment,
    bin_value varbinary(8)
);


insert into bits(bin_value) values(0x05),(0x06);

commit;

select * from bits;


select bit_or(bin_value) from bits;