Question

SQL 求和语句 这两句的查询结果的和，用一句SQL语句表示应该怎么写？

String yszb21="Select Duemoney from busibudget where bkid=21"; String yszb22="Select Duemoney from busibudget where bkid=22"; String 结果和=？

Answer 1

select
sum(case
type
when
1
then
money
else
-money
end)
as
summoney
from
tablename
建议把type修改为type=1
为正
type=-1为负，则sql语句就：
select
sum(type*money)
from
tablename

Answer 2

String
yszb21="Select
Duemoney
from
busibudget
where
bkid=21";
String
yszb22="Select
Duemoney
from
busibudget
where
bkid=22";
String
结果之和="Select
sum(Duemoney)
from
busibudget
where
bkid=21
or
bkid=22";