Select a,b,
nvl(sum(decode(c,'11',1)),0)As 11的件数,
nvl(sum(decode(c,'21',1)),0)As 21的件数,
nvl(sum(decode(c,'31',1)),0)As 31的件数
From table
Group By a,b
nvl(sum(decode(c,'11',1)),0)As 11的件数,
nvl(sum(decode(c,'21',1)),0)As 21的件数,
nvl(sum(decode(c,'31',1)),0)As 31的件数
From table
Group By a,b
sum(decode(c,'21',1,0)) 21的件数,
sum(decode(c,'31',1,0)) 31的件数
from table
group by a,b
+++++++++++
啥意思啊?看不懂,一楼的查询结果就是你要的数据啊
a,
b,
sum(case when c = 11 then 1 else 0 end) 11的件数,
sum(case when c = 21 then 1 else 0 end) 21的件数,
sum(case when c = 31 and ...[其他条件] then 1 else 0 end) 31的件数
from table
group by a,b