如何在 Oracle 中使用 PL/SQL 或 SQL 查询将新行插入到查询结果中？

Question

我正在从多个表中选择数据并希望插入缺失年份的数据。 我可以使用PLSQL或SQL来做到这一点吗？

例如，下面是我的查询的输出：

YEAR  COUNT
----- -----
2012      5
2013      6
2015      2
2016      1
2019      0

我想为缺失的year添加year和count=0 ，最后我应该有这个 -

YEAR  COUNT
----- -----
2012      5
2013      6
2014      0
2015      2
2016      1
2017      0
2018      0
2019      0

Answer 1

创建一个表years包括年度值。

Create table years ( year int)
insert into years values (2010),(2011),(2012), ... etc

然后你需要使用的就是左连接，如下所示：

SELECT y.year,ISNULL(t.val,0)
FROM years y
LEFT OUTER JOIN yourtable t ON t.year=y.year
ORDER BY y.year

Answer 2

一种选择是使用connect by level <= ..含有语法left join用min(..) over (partition by ..)和max(..) over (partition by ..)解析函数作为quxiliary：

with t as
(
 select t0.*, 
        min(year) over (partition by 1) as min_year,
        max(year) over (partition by 1) as max_year
   from t0
)
select t1.year as "year", nvl( t."count" , 0) as "count"
  from
  (
   select distinct level + t.min_year - 1 as year
     from t
   connect by level <= t.max_year - t.min_year + 1 ) t1
  left join t
    on t.year = t1.year
 order by "year"

演示