多选题

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?( )

Question

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;