--select iFabricOrder, iPackageOrder,tPackageTime into #t1 from dbo.mmInDtl where sOrderNo = 'MLS_J210409M' and tPackageTime is not null
declare @i int = 0, @t datetime
--一定要在更新语句中初始化变量,再给字段赋值
update A set @i = case @t when tPackageTime then @i else @i+1 end,
iPackageOrder = @i,
@t = tPackageTime
from (select top 10000 * from dbo.mmInDtl where sOrderNo = 'MLS_J210409M' and tPackageTime is not null order by tPackageTime) A
--select * from #t1 order by tPackageTime
--drop table #t1
select iPackageOrder, tPackageTime from dbo.mmInDtl where sOrderNo = 'MLS_J210409M' and tPackageTime is not null order by tPackageTime