加一个表的别名,应该就可以了
select sum(fs) as getsum
from (select sum(一年级分数) as fs from tablename where 条件
union
select sum(二年级分数) from tablename where 条件
union
select sum(三年级分数) from tablename where 条件) a
加一个表的别名,应该就可以了
select sum(fs) as getsum
from (select sum(一年级分数) as fs from tablename where 条件
union
select sum(二年级分数) from tablename where 条件
union
select sum(三年级分数) from tablename where 条件) a
select sum(fs) as getsum
from (select sum(一年级分数) as fs from tablename where 条件
union
select sum(二年级分数) from tablename where 条件
union
select sum(三年级分数) from tablename where 条件)
http://expert.csdn.net/Expert/topic/1893/1893992.xml?temp=.5286981
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每一个sum(分数) 都需要一个 as fs
否则无法统计到所有fs, sum(fs)
select sum(fs) as getsum
from (select sum(一年级分数) as fs from tablename where 条件
union
select sum(二年级分数) from tablename where 条件
union
select sum(三年级分数) from tablename where 条件)