select count(*) as "所查人数"  from (select * from table_a a, table_b b where a.pid = b.pid) t where t.name like '张%'   and t.age >= 24   and t.age <= 50;select avg(t1.age) as "所查平均年龄"  from (select * from table_a a, table_b b where a.pid = b.pid) t1 where t1.name like '张%'   and t1.sex = '男';