问题： sql 获取每个分组不为零的最小值的整条记录 mssql 2000 用RowNumber order by 要取得值， 然后取 rownumber = 1的数据行
select * ffrom tb a, (select 组, min(值) as 值 from tb where 值 <> 0 group by 组) b
where a.组 = b.组 and a.值 = b.值
如列值有重复时需要加上其它分组里有唯一性列过滤
e.g.
--分组列：groupcol 列值：ID
SELECT *
FROM table1 AS a
WHERE a.id > 0
AND NOT EXISTS ( SELECT 1
FROM table1
WHERE groupcol = a.groupcol
AND id < a.id
AND id > 0 );