Using a tMap to a join between T1 and T2 to get the t2.key, if there exist multiple keys, denomalize all the keys to one line after tMap, write the delete query in a tXXXRow component. eg: tMysqlInput--main--tMap--main--tDenormalize--main(row2)--tFlowToIterate--iterate--tMssqlRow | lookup | tMssqlInput
on tMssqlRow, you can write the query as below:
"delete from T1 where T1.key in "+(String)globalMap.get("row2.columnName")