sql 统计一张表中相同行的个数
------解决思路----------------------
select sum(记录数) from (select 全部列,count(*) 记录数 from table1 group by 全部列 having count(*) > 1) aa
------解决思路----------------------
select col1, col2, col3, count(*) cnt
from table1
group by col1, col2, col3