Oracle SQL - 将两个查询的两个结果合并为一个

Question

我有两个不同的查询：

查询1

select '2013-03-03' As "Week_Of",
count(player_id) as cohort_size
from player
where trunc(create_dtime) > To_Date('2013-Mar-03','yyyy-mon-dd')-7
and trunc(create_dtime) <= To_Date('2013-Mar-03','yyyy-mon-dd')
and world_flag != '1'
;

哪个输出：

Week_of      Cohort_size
2013-03-03      18183

查询2

select '2013-03-03' As "Week_Of", 
count(player_id) as Day_0_Ret
from player
where trunc(init_dtime)-trunc(create_dtime) >= 0
and trunc(create_dtime) > To_Date('2013-Mar-03','yyyy-mon-dd')-7
and trunc(create_dtime) <= To_Date('2013-Mar-03','yyyy-mon-dd')
and world_flag != '1'
;

哪个输出：

Week_of      Day_0_Ret
2013-03-03      15684

我想将这两个查询放在一起，所以我有一个输出的查询：

Week_of         Cohort_Size     Day_0_Ret
2013-03-03       18183              15684

Answer 1

使用case语句进行条件计数：

select '2013-03-03' As "Week_Of",
count(player_id) as cohort_size ,
count(case 
        when trunc(init_dtime)-trunc(create_dtime) >= 0 
        then player_id 
      end) as Day_0_Ret
from player
where trunc(create_dtime) > To_Date('2013-Mar-03','yyyy-mon-dd')-7
and trunc(create_dtime) <= To_Date('2013-Mar-03','yyyy-mon-dd')
and world_flag != '1'
;