You're mixing explicit SQL and implicit SQL there. You cannot do that.
You need to find the SAS code that you need to run, not the SQL you're currently using and it should work directly from PROC EXPORT.
You cannot use explicit SQL here because it only passes your query to the server, not your SAS data.
libname mylibref odbc datasrc=mydatasource schema=dbo;
proc Sql;
Connect to odbc (datasrc=mydatasource); *makes this explicit SQL;
update [db].dbo.sqltable as t1
set EmailList = (select EmailList
from SASemaillist1 t2
where t1.Team = t2.Team)
where team in (select t2.team from SASemaillist1 t2);
disconnect from odbc;
Instead your code should look like the following - note I don't think this is correct and don't know what the correct code should be, just pointing you in the right direction.
proc sql;
update mylibref.sqltable as t1
set EmailList = (select EmailList
from SASemaillist1 t2
where t1.Team = t2.Team)
where team in (select t2.team from SASemaillist1 t2);
quit;