A.COUNT B.TO_NUMBER C.AVG D.SUBSTR
A.共享鎖 B.排它鎖 C.死鎖 D.行級(jí)共享鎖
A.1,3,4,5,2 B.4,1,3,2,5 C.1,3,2,5;4not required D.4,1,5,2;3not required