Question

SQL count 多表总数求和问题

SQL count 多表总数求和问题
如：select count(*) as t from A
select count(*) as t from B
我想把这两次的结果加起来，怎么办啊？

Answer 1

可以这样写:
select
(select count(*) from bumen)+(select count(*) from mrs) as sum_count

如果两个表结果相同的话,也可以用
select count(*) as sum_count
from
(
select * from A
union all
select * from B
) as tmp

Answer 2

select sum(b.rowcnt)
from sysobjects a join sysindexes b on a.id=b.id and a.xtype='u' and b.indid<2
where a.name in('A','B')

Answer 3

select
(select count(*) from bumen)+(select count(*) from mrs) as sum_count