如何用一个SQL语句查询多个表的记录数

sql语句如下：

select t1.num1,t2.num2 from
  (select count(*) num1 from table1) t1,
  (select count(*) num2 from table2) t2

如果要显示这两张表中记录数的总和就是

select t1.num1,+t2.num2 from
  (select count(*) num1 from table1) t1,
  (select count(*) num2 from table2) t2