SELECT
*
FROM
(SELECT
left(charge,4) as charge,
date(stattime) as stattime,
count(*) as num
FROM
Table
WHERE
((left(charge,3)='spc' or left(charge,3)='spw' or left(charge,3)='spm')) AND
stattime>='2011-06-01'
GROUP BY
left(charge,4),
date(stattime)
) a pivot (max(num) for charge in (spca,spcb,spcc,spcd,spwb,spma,spmb,spmc,spmd)) b求改成mysql
SELECT
sum(if(charge='spc',num,0)) as spc,
sum(if(charge='spw,num,0)) as spw
FROM
(SELECT
left(charge,4) as charge,
date(stattime) as stattime,
count(*) as num
FROM
Table
WHERE
((left(charge,3)='spc' or left(charge,3)='spw' or left(charge,3)='spm')) AND
stattime>='2011-06-01'
GROUP BY
left(charge,4),
date(stattime)
) a是不是这样写的?问下
sum(if(charge='spw,num,0)) as spw
这个0的含义是什么呀?