sql - 我可以将查询本身用作 pl/sql 中的过滤器吗？

Question

我知道我没有在问题标题中说清楚。让我解释。
假设我有一张 table SOURCE_TABLE有 1 列，如下所示:

Filter 
------------------|
Name='John' 
Surname = 'Smith' 
Age = '25'

我想用这个表作为过滤器。像下面这样:

SELECT * FROM TARGET_TABLE WHERE (SELECT FILTER FROM SOURCE_TABLE)

我听说评估功能可能对我有帮助，但老实说我不明白如何。
你知道我可以像上面一样使用列作为过滤源的任何方法吗？

编辑1:

DECLARE 
    my_filter VARCHAR2(100); 
    my_query VARCHAR2(500); 
BEGIN 
    my_query := 'SELECT FILTER FROM SOURCE_TABLE WHERE ROWNUM=1'; 
    EXECUTE IMMEDIATE my_query INTO my_filter; 
    EXECUTE IMMEDIATE 'SELECT * FROM TARGET_TABLE WHERE '|| my_filter; 
END; 

@Sujitmohanty30学了以上才想出来的 EXECUTE IMMEDIATE .但是我偶然发现了一个问题。关于最终结果，这需要是动态的，我想在最后看到选择查询的结果。

Answer 1

假设我们有这两个表:

create table TARGET_TABLE(name varchar2(30), surname varchar2(30));
insert into TARGET_TABLE(name,surname) values ('John', 'Doe');
insert into TARGET_TABLE(name,surname) values ('Ann', 'Smith');
insert into TARGET_TABLE(name,surname) values ('Steven', 'Feuerstein');
insert into TARGET_TABLE(name,surname) values ('Steven', 'King');
commit;

create table SOURCE_TABLE(filter) as
select q'[name='John']' from dual union all
select q'[name='Ann']' from dual union all
select q'[name='Steven' and surname='King']' from dual union all
select q'[surname='Feuerstein']' from dual;

然后您可以使用 xmltable 和 dbms_xmlgen.getXMLtype 动态获取此类行:
https://dbfiddle.uk/?rdbms=oracle_18&fiddle=72abdf18b149cf30882cb4e1736c9c33

select *
from SOURCE_TABLE
    , xmltable(
        '/ROWSET/ROW'
        passing dbms_xmlgen.getXMLtype('select * from TARGET_TABLE where '|| SOURCE_TABLE.filter)
        columns 
          name    varchar2(30) path 'NAME',
          surname varchar2(30) path 'SURNAME'
        ) x;

结果:

FILTER                           NAME                           SURNAME
-------------------------------- ------------------------------ ------------------------------
name='John'                      John                           Doe
name='Ann'                       Ann                            Smith
name='Steven' and surname='King' Steven                         King
surname='Feuerstein'             Steven                         Feuerstein