Oracle 在 xmlagg 函数中变得与众不同

Question

我需要在 xmlagg 函数中变得与众不同。例如下一个查询

select
       xmlagg(xmlelement(e, names.name || ' ')).extract('//text()').getclobval()
           within group (order by names.name ) names,
       xmlagg(xmlelement(e, actions.action || ' ')).extract('//text()').getclobval()
           within group ( order by actions.action) actions
from
json_table('[{"name": "Name1"}, {"name": "Name2"}, {"name": "Name3"}]', '$[*]'
                    columns (name varchar2 path '$.name')) names,
json_table('[{"action": "Call"}, {"action": "Write"}, {"action": "Write"}]', '$[*]'
                    columns (action varchar2 path '$.action')) actions

返回

NAMES                                                 | ACTIONS
-----------------------------------------------------------------------------------------------------------
Name1 Name1 Name1 Name2 Name2 Name2 Name3 Name3 Name3 | Call Write Write Call Write Write Call Write Write 

我需要得到类似的结果

NAMES             | ACTIONS
-------------------------------
Name1 Name2 Name3 | Call Write  

Answer 1

我认为首先在子查询中选择不同的值更简单：

select 
    (
        select xmlagg(xmlelement(e, name || ' ') order by name).extract('//text()').getclobval()
        from (
            select distinct name
            from json_table(
                '[{"name": "Name1"}, {"name": "Name2"}, {"name": "Name3"}]', '$[*]'
                columns (name varchar2 path '$.name')
            ) names
        ) n
    ) names,
    (
        select xmlagg(xmlelement(e, action || ' ') order by action).extract('//text()').getclobval()
        from (
            select distinct action
            from json_table(
                '[{"action": "Call"}, {"action": "Write"}, {"action": "Write"}]', '$[*]'
                columns (action varchar2 path '$.action')
            ) actions
        ) a
    ) actions
from dual

注意xmlagg() 的order by 更适合在函数中。

Demo on DB Fiddle：

姓名 |行动 :----------------- | :---------- 姓名1 姓名2 姓名3 |调用写入