Oracle使用5个条件加入2个视图

Question

我必须加入2个视图view_a和view_b。
view_a具有列id，address1，address2，city，state，cntry view_b id，frst_name，last_name，type，date，job_title

理想的结果
id，名称，地址1，地址2，城市，州，国家，职务

我查询的条件是：
1.在id列上加入两个视图。
2.按日期排序
3.串联first_name和last_name
4.类型等于“军官”
5.如果有多名官员，则仅产生一名官员，即基于日期的第一行。
6.如果没有人员，则结果中的name和job_title列的值为空。

我使用过的查询：

   select 
       * 
   from  
      view_a A 
   join 
   (
          select 
              (first_name || ' ' || last_name) as name,
              job_title,
              id 
          from 
              view_b 
                   where 
              type = 'officer' 
                    and 
               id is not null 
            order by date desc fetch first 1 row only
   ) B
   on A.id=B.id  

但是此查询仅产生一个结果。 我正在使用Oracle 12c。 这些视图中大约有80万条记录。

Answer 1

你可以这样做：

select id,
    name,
    address1,
    address2,
    city,
    state,
    cntry,
    job_title
(select 
    a.id,
    nvl2(nvl(b.first_name, b.last_name),b.first_name||' '||b.last_name,null) Name,
    a.address1,
    a.address2,
    a.city,
    a.state,
    a.cntry,
    b.job_title,
    a.date
    row_number() over (partition by a.id order by a.date desc nulls last) rn
from  
    view_a a left outer join
    view_b b
on a.id = b.id
and b.type = 'officer')
where rn = 1
order by date desc nulls last;

Answer 2

以下还解决了该问题：

SELECT *
FROM view_a a
   LEFT JOIN (SELECT name, job_title, id
           FROM (SELECT (first_name || ' ' || last_name) AS name,
                        job_title,
                        id,
                        ROW_NUMBER() OVER(PARTITION BY id ORDER BY date DESC) rn
                   FROM view_b
                  WHERE TYPE = 'officer' AND id IS NOT NULL)
          WHERE rn = 1) b
       ON a.id = b.id