多选题

假设MySQL数据库

Question

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