Sorting 在timeuuid类型主键上的Cassandra排序

我是卡桑德拉的新手。我希望获得基于主键（即timeuuid）的排序结果集。我的桌子结构很简单

CREATE TABLE user_session
(
  session_id timeuuid,
  ip inet,
  device_type int,
  is_active int,
  last_access_time timestamp,
  logout_reason text,
  logout_type int,
  start_time timestamp,  
  uid int,
  PRIMARY KEY(session_id)
);

---

有人能帮我吗。

您不能在主列的查询中使用order by。它仅在群集列上受支持。您必须更改此表才能执行此类查询。它可能看起来像这样：

CREATE TABLE user_session
(
user_id int,
session_id timeuuid,
ip inet,
device_type int,
is_active int,
last_access_time timestamp,
logout_reason text,
logout_type int,
start_time timestamp,  
uid int,
PRIMARY KEY(user_id, session_id)
);

CREATE TABLE user_session
(
user_id int,
session_id timeuuid,
ip inet,
device_type int,
is_active int,
last_access_time timestamp,
logout_reason text,
logout_type int,
start_time timestamp,  
uid int,
PRIMARY KEY(user_id, session_id)
) WITH CLUSTERING ORDER BY (session_id ASC);

然后，您的查询将如下所示：

select * from user_session where user_id=5 order by session_id ASC;

基本上，您需要一些主键，用于搜索只允许

EQ

和

IN

关系的数据，因此您不能有

user\u id>5

或类似的内容，然后您可以通过集群列对结果进行排序，该列在您的案例中是

session\u id

---

Zoran

您可以使用ORDER BY from表定义，以便在插入过程中保持正确的顺序。

PRIMARY KEY

定义具有分区键

user\u id

和用于排序的集群列

session\u id

。它可能看起来像这样：

CREATE TABLE user_session
(
user_id int,
session_id timeuuid,
ip inet,
device_type int,
is_active int,
last_access_time timestamp,
logout_reason text,
logout_type int,
start_time timestamp,  
uid int,
PRIMARY KEY(user_id, session_id)
);

CREATE TABLE user_session
(
user_id int,
session_id timeuuid,
ip inet,
device_type int,
is_active int,
last_access_time timestamp,
logout_reason text,
logout_type int,
start_time timestamp,  
uid int,
PRIMARY KEY(user_id, session_id)
) WITH CLUSTERING ORDER BY (session_id ASC);