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我有 2 个查询,当在内部选择查询中移动 where 子句时,这两个查询都显示不同的结果。

select destination_number, count(*) as cnt from (
select caller_id_number as caller_id_number, destination_number as destination_number 
from Final1  where start_stamp > '2013-01-01 00:00:00' and start_stamp < '2013-01-26 00:00:00' 
group by caller_id_number, destination_number) 
where destination_number = '1234' 
group by  destination_number 

计数结果:294636

select destination_number, count(*) as cnt from (
select caller_id_number as caller_id_number, destination_number as destination_number 
from Final1  where destination_number = '1234' and start_stamp > '2013-01-01 00:00:00' and start_stamp < '2013-01-26 00:00:00' 
group by caller_id_number, destination_number) 
group by  destination_number 

计数结果:310627

我想知道为什么计数会改变以及哪个查询是正确的。

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