最近一直在面试，遇到一种面试题记录一下留个眼熟吧。
sql：
select rstime,
sum(case result when '胜' then 1 else 0 end)as 胜,
sum(case result when '负' then 1 else 0 end)as 负
from result group by rstime;
sql：
select pid,
sum(CASE did WHEN '01' THEN
punm
ELSE
0 end) AS s1id,
sum(CASE did WHEN '02' THEN
punm
ELSE
0 end) AS s2id,
sum(CASE did WHEN '03' THEN
punm
ELSE
0 end) AS s3id FROM product
GROUP BY pid;