单选题：SQL命令--修改user表里面id=1的username修改为"QQQ"，修改password为"999"，SQL语句为：（ ）。
修改user表里面id=1的username修改为"QQQ"，修改password为"999"，SQL语句为：（ ）。
A.update user username='QQQ',password='999' where id=1;
B.update user set username='QQQ' and password='999' where id=1;
C.update user set username='QQQ',password='999' id=1;
D.update user set username='QQQ',password='999' where id=1;
答案：D
A.update user username='QQQ',password='999' where id=1;
B.update user set username='QQQ' and password='999' where id=1;
C.update user set username='QQQ',password='999' id=1;
D.update user set username='QQQ',password='999' where id=1;
答案：D
