Oracle自定义行转列函数

--行转列自定义函数，只针对TABLE1表
--paramType是参数类型，用于判断，param1和param2是条件参数
create or replace function My_concat(paramType in integer,param1 in varchar2,param2 in varchar2) return varchar2
is 
    resultStr varchar2(2000);
begin 
    if paramType = 1 then 
        --定义游标
        for temp_cursor1 in (select CONTA_ID FROM TABLE1 WHERE FORM_ID=param1 and orderType=param2)
        loop
            resultStr:=resultStr||temp_cursor1.CONTA_ID||‘,‘;
        end loop;
    
    elsif paramType = 2 then 
        for temp_cursor2 in (select CONTA_TYPE FROM TABLE1 WHERE FORM_ID=param1 and orderType=param2)
        loop
            resultStr:=resultStr||temp_cursor2.CONTA_TYPE||‘,‘;
        end loop;
        
    elsif paramType = 3 then 
        for temp_cursor3 in (select CONTA_WEIGHT FROM TABLE1 WHERE FORM_ID=param1 and orderType=param2)
        loop
            resultStr:=resultStr||temp_cursor3.CONTA_WEIGHT||‘,‘;
        end loop;
    
    end if;
    
    resultStr:=rtrim(resultStr,‘,‘);
    return resultStr;
    
end;


--执行例子：
select A.COLUMN1,A.COLUMN2,A.COLUMN3
       My_concat(1,A.COOLUMN1,A.COLUMN2) AS CONTA_IDS,
       My_concat(2,A.COOLUMN1,A.COLUMN2) AS CONTA_TYPES,
       My_concat(3,A.COOLUMN1,A.COLUMN2) AS CONTA_WEIGHTS
from TABLE1 AS B LEFT JOIN TABLE2 A 
ON A.COOLUMN1=B.FORM_ID AND A.COLUMN2=B.orderType