依据二度人脉推荐好友sql

friend表结构

DROP TABLE IF EXISTS FRIEND;

create table friend(

    uid        bigint not null comment '用户标识',

    friend_uid    bigint not null comment '申请加为好友的用户标识',

    sys_create_date datetime not null comment '申请时间',

    sys_last_update datetime not null comment '更新时间',

    state tinyint not null comment '好友状态 0 ： 删除, 1:申请好友, 2 : 好友',

    primary key(uid, friend_uid)

)ENGINE=InnoDB DEFAULT CHARSET=utf8 COMMENT '好友表';

select friend_uid from

friend where state=2 and

uid in (select friend_uid from friend where uid=13 and state=2)

and friend_uid not in (select friend_uid from friend where uid=13 ) and friend_uid != 13 limit 6

uid为当前用户的ID，为id为13的用户查询二度人脉好友