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MySQL COUNT SUM

 select
count(*) as mcount ,
left(create_time,10) as ptime ,
count(if(receive_msg is null,id,null)) as nullcount ,
count(if(receive_msg = '1',receive_msg,null)) as apfcount ,
count(if(receive_msg = '2',receive_msg,null)) as dttcount ,
count(if(receive_msg = '3',receive_msg,null)) as dicount
from
t_votes
where
left(create_time,7)>='$pearly'
and
left(create_time,7)<='$plate'
group by
ptime ;

COUNT(*)´øÉÏֵΪNULLµÄ
COUNT(table_name)²»´øÖµÎªNULLµÄ
¼ÆÊý²»ÇóºÍ,¿ÉÓÃÆäËû×Ö¶ÎÌæ´ú
select
count(*) as mcount ,
left(create_time,10) as ptime ,
SUM(if(receive_msg is null,id,0)) as nullcount ,
SUM(if(receive_msg = '1',receive_msg,0)) as apfcount ,
SUM(if(receive_msg = '2',receive_msg,0)) as dttcount ,
SUM(if(receive_msg = '3',receive_msg,0)) as dicount
from
t_votes
where
left(create_time,7)>='$pearly'
and
left(create_time,7)<='$plate'
group by
ptime ;

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