select * from (
select row_number() over(partition by Gid order by Gid ASC) as RowN, *
from(
select b.Gid, a.OrderNo,b.Carcode from fit_CarOrder a inner join Fit_CarDetail b
on a.OrderNo=b.DetailNo
inner join Fit_OrderDetail c on a.Gid=c.OrderGid
where a.orderno=‘201909180000038000099988‘
) as bb)
as tt where tt.RowN=1
分组排序对于主单对应多个明细 分组排序去重 如果 明细中对应到第三个明细中也存在对应的主单信息时 最好取决于第二个表的明细ID来排序分组筛选重复项
row_number() over()分组排序功能 partition by 用于给结果集分组
原文：https://www.cnblogs.com/Warmsunshine/p/11549787.html