Question

我的表“ COMMA_SEPERATED”看起来像这样

    id | referrals
----------------------------------------
    1  | [{"risk_score":"1"}]
    2  | [{"risk_score":"2"}]

我想将每个城市分开作为新记录，所以我的SQL是：（工作正常）

ID  NAME CITY
--- ---- -----------------------------
1   RAJ  CHENNAI, HYDERABAD, JABALPUR
2   SAM  BHOPAL,PUNE

我想将这段SQL转换为一个函数，以便我可以像这样简单地调用该函数

SELECT id, TRIM(CITY_NEW)
FROM COMMA_SEPERATED, xmltable
(
    'if (contains($X,",")) then ora:tokenize($X,"\,") else $X'
    passing city AS X
    columns CITY_NEW varchar2(4000) path '.'
);

输出：

SELECT id, split_function(city) FROM COMMA_SEPERATED

有人可以帮忙吗？我是PL / SQL的新手。

Answer 1

除了@Alex所显示的内容之外，您还可以创建一个object并通过object返回function。见下文：

--Created an object to hold your result columns
create or replace type Obj IS OBJECT (id number, city varchar2(20));
/
--Table of object
create or replace type var_obj is table of Obj;

/
--Function with return as with Object type.
create or replace function splt_fnct
return var_obj
as
var var_obj:=var_obj();

begin
Select obj(col,col1)
bulk collect into var
from (
Select  distinct  col , regexp_substr(col1,'[^,]+',1,level) col1
from tbl
connect by regexp_substr(col1,'[^,]+',1,level) is not null
order by 1);

return var;
end;

/
--Selecting result   

 select *  from table(splt_fnct);

编辑：我正在尝试@Alex解决方案，但出现如下所示的错误：

create or replace function splt_fnct(input_strng varchar2)
return var_obj
as
var var_obj:=var_obj();

begin
Select obj(col,col1)
bulk collect into var
from (
select tbl.col, t.rslt --<--This column name should the same as used in colmns clause in the below query. Its giving error "invalid column". How to handle this case.
FROM tbl, xmltable
(
    'if (contains($X,",")) then ora:tokenize($X,"\,") else $X'
    passing col1 AS X
    columns input_strng varchar2(4000) path '.'
) t
);
return var;
end;

/

根据@Alex建议进行更正：

create or replace function splt_fnct(input_strng varchar2)
return var_obj
as
var var_obj:=var_obj();

begin

select obj(tbl.col, t.rslt) 
bulk collect into var
FROM tbl, xmltable
(
    'if (contains($X,",")) then ora:tokenize($X,"\,") else $X'
    passing input_strng AS X
    columns rslt  varchar2(4000) path '.'
) t;

return var;
end;

/

Answer 2

您要获取的查询：

SELECT id, split_function(city) FROM COMMA_SEPERATED

无效，因为您试图为每个源行返回多个行。不幸的是，您必须使它复杂一些。

如果目标是隐藏拆分机制，那么我能想到的最接近的方法是创建一个返回字符串集合的函数，该字符串可以是pipelined：

create or replace function split_function (p_string varchar2)
return sys.odcivarchar2list pipelined as
begin
  for r in (
    select result
    from xmltable (
      'if (contains($X,",")) then ora:tokenize($X,"\,") else $X'
      passing p_string as x
      columns result varchar2(4000) path '.'
    )
  )
  loop
    pipe row (trim(r.result));
  end loop;
end split_function;
/

您建议的通话将为您提供每个ID包含集合的一行：

select id, split_function(city) from comma_seperated;

        ID SPLIT_FUNCTION(CITY)
---------- -----------------------------------------------------------------
         1 ODCIVARCHAR2LIST('CHENNAI', 'HYDERABAD', 'JABALPUR')
         2 ODCIVARCHAR2LIST('BHOPAL', 'PUNE')

这不是您想要的；但是您可以使用表集合表达式和交叉联接将其转换为多行：

select cs.id, t.column_value as city
from comma_seperated cs
cross join table(split_function(cs.city)) t;

        ID CITY                          
---------- ------------------------------
         1 CHENNAI                       
         1 HYDERABAD                     
         1 JABALPUR                      
         2 BHOPAL                        
         2 PUNE

db<>fiddle demo。

这并不像您希望的那样简单，但是可以说它比交叉连接到xmltable()还要好，特别是如果您想在多个地方重用该拆分逻辑/功能以及隐藏拆分方式的详细信息-如果您愿意，可以轻松更改机制，例如使用更常见的正则表达式进行拆分。

将一段SQL转换为Oracle函数

2 个答案: