例如
select count(1) from client where member=5 and rank=1
这个是一个统计
根据不同的rank会做多个统计但这样效率很低(要多次统计)
能不能一次过返回rank为1 2 3 4 5这样的数据呢
select count(1) from client where member=5 and rank=1
这个是一个统计
根据不同的rank会做多个统计但这样效率很低(要多次统计)
能不能一次过返回rank为1 2 3 4 5这样的数据呢
sum(case rank when 1 then 1 else 0 end) as [rank1],
sum(case rank when 2 then 1 else 0 end) as [rank2],
sum(case rank when 3 then 1 else 0 end) as [rank3],
sum(case rank when 4 then 1 else 0 end) as [rank4],
sum(case rank when 5 then 1 else 0 end) as [rank5]
from
client
where
member=5
rank,
count(1) as cnt
from
client
where
member=5
group by
rank