Oralce和DB2都支援的語法：
UPDATE A SET (A1, A2, A3) = (SELECT B1, B2, B3 FROM B WHERE A.ID = B.ID)
複製程式碼MS SQL Server不支援這樣的語法，相對應的寫法為：
UPDATE A SET A1 = B1, A2 = B2, A3 = B3 FROM A LEFT JOIN B ON A.ID = B.ID
複製程式碼個人感覺MS SQL Server的Update語法功能更為強大。MS SQL SERVER的寫法：
UPDATE A SET A1 = B1, A2 = B2, A3 = B3 FROM A, B WHERE A.ID = B.ID
複製程式碼在Oracle和DB2中的寫法就比較麻煩了，如下：
UPDATE A SET (A1, A2, A3) = (SELECT B1, B2, B3 FROM B WHERE A.ID = B.ID)
WHERE ID IN (SELECT B.ID FROM B WHERE A.ID = B.ID)
複製程式碼或者
update test_a a set (a.name,a.age)= (select b.name,b.age from test_b b where a.id = b.id)
where exists (select * from test_b c where c.id=a.id)
複製程式碼