mysql将子查询排除在联接之外

我想计算（pid=pid_raw）占pid_raw总数的百分比，其中date_raw在日期前31天

我知道我可以用一个内部联接部分地完成这项工作，但因为我想得到百分比，因此需要pid_raw的总计数，而不管匹配与否，该子查询不能成为内部联接的一部分。如何编写子查询以获得不受内部联接影响但符合where子句的pid_raw的总计数

table1
date          pid
2015-06-01    223
2015-06-01    333 
2015-05-01    124 
2015-05-01    543 


table2
date_raw      pid_raw
2015-05-30    223
2015-05-15    111
2015-05-03    333 
2015-05-02    242
2015-05-05    300
2015-04-10    124
2015-04-15    543
2015-04-09    511


Example output
date         pid_percentage
2015-06-01     0.40           <-------(2/5)
2015-05-01     0.67            <------(2/3)

表1
日期pid
2015-06-01    223
2015-06-01    333 
2015-05-01    124 
2015-05-01    543 
表2
日期\u原始pid\u原始
2015-05-30    223
2015-05-15    111
2015-05-03    333 
2015-05-02    242
2015-05-05    300
2015-04-10    124
2015-04-15    543
2015-04-09    511
示例输出
日期pid_百分比
2015-06-01 0.40我的建议是在日期加入，然后使用条件聚合进行计算：

select t1.date,
       count(distinct case when t1.pid = t2.pid_raw then t1.pid end) as NumMatches,
       (count(distinct case when t1.pid = t2.pid_raw then t1.pid end) / 
        count(distinct case when t1.pid = t2.pid_raw then t2.pid_raw end) 
       ) as percentage_pid
from table1 t1 left join
     table2 t2
     on t2.date_raw between t1.date - interval 31 day and t1.date
group by t1.date;

谢谢，虽然这会运行，但在我获得任何输出之前，它会花费太长时间和超时。有更好的方法吗？
select t1.date,
       count(distinct case when t1.pid = t2.pid_raw then t1.pid end) as NumMatches,
       (count(distinct case when t1.pid = t2.pid_raw then t1.pid end) / 
        count(distinct case when t1.pid = t2.pid_raw then t2.pid_raw end) 
       ) as percentage_pid
from table1 t1 left join
     table2 t2
     on t2.date_raw between t1.date - interval 31 day and t1.date
group by t1.date;