1.索引
 
a.创建
 
create index idx_name on fdh_client_info(name);--普通索引(单列索引)
 
create unique index uni_idx_id on fdh_client(id); --唯一索引
 
create index union_idx_name_addr on fdh_client(name, address);--联合索引
 
b.查询索引