简单的sql语句(union表联合求和)马上给分 select count(*) from ( select a from t_a where union select a from t_b where )t 解决方案 » 免费领取超大流量手机卡,每月29元包185G流量+100分钟通话, 中国电信官方发货 select sum(a)from(select a from t_a whereunion select a from t_b where;) test select sum(a)from(select a from t_a whereunion Allselect a from t_b where;) test select 总和=sum(a),个数=count(a)from(select a from t_a whereunion select a from t_b where;) test select sum(a) as [sum]from(select a from t_a where ....union allselect b from t_b where ....)t 数据库简单问题,希望高手们帮帮初学者谢谢 SQL怎么在数据库里知道语句执行完成了 如何将2008-01-17 14:08:04.850字符串转化为sql server中日期格式而不减少精确度 实例? 初学数据库,请各位高手提供几个好网站,谢谢! 如何输入约束范围以外的数据?分不够可以加 帮帮忙,我的数据是不是完蛋了。我急,我急,我急急急!!! 有无办法减小VFP6的两个DLL文件尺寸 已经正式上线的数据库如何配置对等复制? 急!单元格里的内容怎么重新归类查询 一个简单的SQL条件查询语句...... 如何写查询语句?
from
(
select a from t_a where
union
select a from t_b where;
) test
from
(
select a from t_a where
union All
select a from t_b where;
) test
from
(
select a from t_a where
union
select a from t_b where;
) test
from(
select a from t_a where ....
union all
select b from t_b where ....
)t