三个表:BOOK,BOOKIN,BOOKOUTselect book.bok_id,book.bok_name,book.bok_zz,book.bok_cbs,
sum(bookin.bokin_num)as num1,sum(bookout.bokout_num)as num2
from book,bookin,bookout
where book.bok_id=bookin.bok_id and book.bok_id=bookout.bok_id
group by book.bok_id,book.bok_name,book.bok_zz,book.bok_cbsbookin.bokin_num实际为30 bookout.bokout_num实际为3可这样查询出来分别是90 和6啦!
sum(bookin.bokin_num)as num1,sum(bookout.bokout_num)as num2
from book,bookin,bookout
where book.bok_id=bookin.bok_id and book.bok_id=bookout.bok_id
group by book.bok_id,book.bok_name,book.bok_zz,book.bok_cbsbookin.bokin_num实际为30 bookout.bokout_num实际为3可这样查询出来分别是90 和6啦!
sum(bookin.bokin_num)as num1,sum(bookout.bokout_num)as num2
from book,bookin,bookout
where (book.bok_id=bookin.bok_id) and (book.bok_id=bookout.bok_id)
group by book.bok_id,book.bok_name,book.bok_zz,book.bok_cbs
我在查询分析器将它精减为这样:这句查询语言得出的结果仍为90,6,而实际上应该是30,3
select sum(bookin.bokin_num),sum(bookout.bokout_num)
from bookin,bookout就拿这条查询来说吧,我的目的就是取得两个表中的字段合计数,并返回一个数据集。
有什么别的办法实现吗?
你有没有试过啊,我估计不行,问题不在那里啊!
我有空一定要试一下啊!