select @count = sum(data) from
(
select count(*)  as data from #tempregion
union 
select count(*)  as data from #tempmetro
union
select count(*)  as data from #tempcity
union
select count(*)  as data from #tempzips
) a

select (select count(*) from tab1) count_1, (select count(*) from tab2) count_2 from dual;

作为附加信息，要在SQL Server中完成同样的事情，您只需要删除查询的“FROM dual”部分。

我很快想到了:

Select (select count(*) from Table1) as Count1, (select count(*) from Table2) as Count2

注意:我在SQL Server中测试了这个，所以从Dual是不必要的(因此存在差异)。

SELECT (SELECT COUNT(*) FROM table1) + (SELECT COUNT(*) FROM table2) FROM dual;

我的经验是使用SQL Server，但是你能做到:

select (select count(*) from table1) as count1,
  (select count(*) from table2) as count2

在SQL Server我得到的结果，你是后。