看看这条语句错在哪里？

[tianlei521]

select
min(case when jysj>='2005/11/01' and jysj<='2005/11/30' then lcb end) as sqlc,
max(case when jysj>='2005/11/01' and jysj<='2005/11/30' then lcb end) as bqlc,
sum(case when jysj>='2005/11/01' and jysj<='2005/11/30' then convert(numeric(20,2),lcb)
when jysj>='2005/11/01' and jysj<='2005/11/30' then -convert(numeric(20,2),lcb)
end) as bqxs,
sum(case when jysj>='2005/11/01' and jysj<='2005/11/30' then convert(numeric(20,2),jyl)
when jysj>='2005/11/01' and jysj<='2005/11/30' then -convert(numeric(20,2),jyl)
end) as bqyy,
a.cldm
from
car_jyxx a
where
exists(select 1 from car_clxx where cldm=a.cldm)
group by
a.cldm

执行后得到的bqxs的值应该是bqlc减去sqlc的值，可是怎么得到的是两个相加的值呢？帮忙啊！

[子陌红尘]

看仔细，两个when之后的条件语句是相同的，因此只执行第一个when后的then

sum(case
when jysj>='2005/11/01' and jysj<='2005/11/30' then convert(numeric(20,2),lcb)
when jysj>='2005/11/01' and jysj<='2005/11/30' then -convert(numeric(20,2),lcb)
end) as bqxs,

[wgsasd311]

select
min(case when jysj>='2005/11/01' and jysj<='2005/11/30' then lcb end) as sqlc,
max(case when jysj>='2005/11/01' and jysj<='2005/11/30' then lcb end) as bqlc,

( max(case when jysj>='2005/11/01' and jysj<='2005/11/30' then convert(numeric(20,2),lcb)
else 0 end)-
min(case when jysj>='2005/11/01' and jysj<='2005/11/30' then -convert(numeric(20,2),lcb)
else 0 end) )as bqxs,
sum(case when jysj>='2005/11/01' and jysj<='2005/11/30' then convert(numeric(20,2),jyl)
when jysj>='2005/11/01' and jysj<='2005/11/30' then -convert(numeric(20,2),jyl)
end) as bqyy,
a.cldm
from
car_jyxx a
where
exists(select 1 from car_clxx where cldm=a.cldm)
group by
a.cldm

[tianlei521]

子陌红尘老兄，要怎样才能得到我要的结果呢？