sql多个表查询结果合并，并且分开字段，除法小数处理

select t1.c1,
       t2.c2,
       cast(cast(t2.c2 - t1.c1 as decimal(10, 2)) /
        cast(t2.c2 as int) as decimal(10, 2))
   from (select count(*) realCount
      from t1) t1,
     (select count(*) planCount
      from t2 ) t2;

##除法，要转decimal再除