要统计多张表的总数要怎么做
比方说有12张表   tab_1(1月份),tab_2(2月份).........tab_12(12月份). 
 select   count(*)   from   tab_1   那怎么把12张表的总数都统计出来,写一条语句!!
------解决方案--------------------select sum(num) from 
 (select count(*) as num from tab_1 
 union all 
 select count(*) as num from tab_2 
 .. 
 .. 
 select count(*) as num from tab_12 
 )