假设 MySQL 数据库表:create table T{ k int unsigned not null auto_increment,a date,b varchar (24) ,c int ,d varchar (24) ,primary key (k) ,unique key a_index (a DESC ,b DESC) ,key k1 ( b ) ,key k2 (c ) ,key k3 (d) ) ;如下哪些 sql 语句查询能较好的利用索引( ) 。
A.select b from WHERE b like 'aaa%'; B.select a ,b from T WHERE a='2015- 10-25' ORDER BY b ASC ,c ASC; C.select a ,b ,c from T WHERE a='2015- 10-25' ORDER BY b ASC; D.select a ,b ,c from T WHERE a='2015- 10-25' ORDER BY a ,b;正确答案A
