使用timeuuid CQL的聚类顺序

Question

我的用法

create table demo(oid int,cid int,ts timeuuid,PRIMARY KEY (oid,cid,ts)) WITH CLUSTERING ORDER BY (ts DESC);

I want the result for all the below queries to be in DESC order of timestamp

select * from demo where oid = 100;
select * from demo where oid = 100 and cid = 10;
select * from demo where oid = 100 and cid = 100 and ts > minTimeuuid('something');

cqlsh:v> create table demo(oid int,cid int,ts timeuuid,PRIMARY KEY (oid,cid,ts))     WITH CLUSTERING ORDER BY (ts desc);
Bad Request: Missing CLUSTERING ORDER for column cid

Answer 1

CREATE TABLE example ( a int, b int, c int, d int, PRIMARY KEY (a,b,c)) WITH CLUSTERING ORDER BY (b DESC , c ASC ) ;

是对多列进行排序的正确语法。

对于您的特定应用程序，您实际上试图从明显不同类型的查询中获得结果。在Cassandra中，最好将每个表设置为对特定查询的响应。

例如（对您的应用程序了解不多）

select * from demo where oid = 100 and cid = 100 and ts > minTimeuuid('something');
select * from demo where oid = 100 and cid = 10;

create table demo_oct(oid int,cid int,ts timeuuid, body, other ...., PRIMARY KEY ((oid,cid),ts)) WITH CLUSTERING ORDER BY (ts DESC);

create table demo_ot(oid int,cid int,ts timeuuid, body, other ...., PRIMARY KEY (oid,ts)) WITH CLUSTERING ORDER BY (ts DESC);

在应用程序端，您将同时插入这两个表。

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