1.  Pull one row from each result set.
LOOP:
2.  Compare T1 keys to T2 keys
3.  If T1 is "larger"
        Generate a "delete" for T2 keys
        "Advance" T2, return to loop
4.  If T1 is "smaller"
         Generate an "insert" for T1 keys and values
         "Advance" T1, return to loop
5.  Compare T1 and T2 values
6.  If different, generate an "update" statement
7.  "Advance" both T1 and T2, return to loop