Question

我必须加入2次观看view_a和view_b view_a具有列id，地址1，地址2，城市，州，cntry view_b id，frst_name，last_name，type，date，job_title

期望的结果
ID，名称，地址1，地址，城市，州，CNTRY，JOB_TITLE

我的查询条件是：
1.加入id列的两个视图 2.按日期排序desc
3.连接first_name和last_name
4.类型等于“官员”
5.如果有一名以上的官员，那么只产生一名官员，即根据日期排在第一位 6.如果没有人员，则结果中的name和job_title列的值为null。

查询我使用过：

   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

但是这个查询只产生一个结果。我正在使用Oracle 12c。这些视图中有大约800K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

以下也解决了这个问题：

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

Oracle使用5个条件加入2个视图

2 个答案: