SQL——填写没有结果的日期

我有一个疑问：

Select Trunc(Create_Dtime),Count(Trunc(Create_Dtime)) as Day_0 From Player
Group By Trunc(Create_Dtime)
Order By Trunc(Create_Dtime) Asc

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它会返回日期，但如果某个日期没有任何结果，则会跳过该日期。我想填写从8-05-12到现在的所有日期，如果这些日期没有任何值，只需在结果中填入0即可

根据要创建行的方式，您可以创建一个或使用Oracle语法动态生成行

或者，刚刚注意到你的约会限制：

with the_dates as (
  select to_date('07-05-2012','dd-mm-yyyy') + level as the_date
    from dual
 connect by level <= trunc(to_date('07-05-2012','dd-mm-yyyy') - sysdate)
         )
 select td.the_date, count(trunc(p.create_dtime))
   from the_dates td
   left outer join player p
     on td.the_date = trunc(p.create_dtime)
  group by td.the_date
  order by td.the_date

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对于所有这些，我建议在您的玩家表上的trunccreate\u dtime上创建一个索引。

Ben，感谢您检查这些，但上面的任何一项都不起作用。我不确定您所说的索引是什么意思，我的SQL级别是非常新手。你能不能再扩展一点？什么不起作用？对于索引，我只能建议你或谷歌一点；它们基本上是访问表的一种快速方式，但有许多复杂之处。

with the_dates as (
  select max(trunc(Create_Dtime)) as max_date
       , min(trunc(Create_Dtime)) as min_date
    from player 
         )
select c.the_date, count(trunc(p.Create_Dtime))
  from calender c
  join the_dates td
    on c.the_date between td.min_date and td.max_date
  left outer join join player p
    on c.the_date = trunc(p.Create_Dtime)
 group by c.the_date
 order by c.the_date

with the_dates as (
  select to_date('07-05-2012','dd-mm-yyyy') + level as the_date
    from dual
 connect by level <= trunc(to_date('07-05-2012','dd-mm-yyyy') - sysdate)
         )
 select td.the_date, count(trunc(p.create_dtime))
   from the_dates td
   left outer join player p
     on td.the_date = trunc(p.create_dtime)
  group by td.the_date
  order by td.the_date