select
sum(0)/moneysum,
depname
from
(
select
id,name,money,d.name as depname
(select count(0) from Person) as moneysum
from Person p
left join Department d on d.id = p.depno
where money>2000
)group by depname这个写法性能好不?
sum(0)/moneysum,
depname
from
(
select
id,name,money,d.name as depname
(select count(0) from Person) as moneysum
from Person p
left join Department d on d.id = p.depno
where money>2000
)group by depname这个写法性能好不?
SUM(CASE
WHEN PT.MONEY > 2000 THEN
1
ELSE
0
END) / COUNT(PT.ID) AS RATE
FROM PERSON PT DEPARTMENT DT
WHERE DT.ID = PT.DEPNO
GROUP BY DEPNAME