>>840
なぜ質問をsageで書く（;´Д｀）

Bの内容をAの内容で更新
UPDATE B
SET (B.col1, B.Col2, ...) =
(SELECT A.col1, A.col2, ... FROM A
WHERE A.key1 = B.key1 AND A.key2 = B.key2 AND ... );

AにあってBに無いレコードをBに追加
INSERT INTO B (key1, key2, ... ,col1, col2, ...)
SELECT key1, key2, ... ,col1, col2, ...
FROM A
WHERE (A.key1, A.key2, ...) NOT IN
(SELECT B2.key1, B2.key2, ... FROM B B2
WHERE B2.key1 = A.key1 AND B2.key2=A.key2 AND ...)

両方とも未検証。特に２つ目は地震内。ちなみにOracle Onlyね。