A simple way to do this:

update #Table1

set #Table1.SID = #Table2.aID

from #Table2

where #Table1.Sno = #Table2.Sno ;

DISTINCT(sj.name)

That doesn't return unique names, distinct returns unique rows:

DISTINCT

Specifies that only unique rows can appear in the result set. Null values are considered equal for the purposes of the DISTINCT...

I believe the records you see when you "View History" of a job are in msdb.dbo.sysjobhistory.