You are viewing a plain text version of this content. The canonical link for it is here.
Posted to commits@cassandra.apache.org by "Andres de la Peña (Jira)" <ji...@apache.org> on 2022/11/18 12:47:00 UTC
[jira] [Updated] (CASSANDRA-18060) Within collection aggregation functions
[ https://issues.apache.org/jira/browse/CASSANDRA-18060?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Andres de la Peña updated CASSANDRA-18060:
------------------------------------------
Description:
The new mechanism for dynamically building native functions introduced by CASSANDRA-17811 can be used to provide within-collection aggregation functions. We can use that mechanism to add new CQL functions to get:
* The number of items in a collection.
* The max/min items of a collection.
* The sum/avg of the items of a numeric collection.
* The keys or the values of a map.
For example:
{code:java}
CREATE TABLE k.t (k int PRIMARY KEY, l list<int>, m map<int, int>);
INSERT INTO t(k, l, m) VALUES (0, [1, 2, 3], {1:10, 2:20, 3:30});
> SELECT map_keys(m), map_values(m) FROM t;
system.map_keys(m) | system.map_values(m)
--------------------+----------------------
{1, 2, 3} | [10, 20, 30]
> SELECT collection_count(m), collection_count(l) FROM t;
system.collection_count(m) | system.collection_count(l)
----------------------------+----------------------------
3 | 3
> SELECT collection_min(l), collection_max(l) FROM t;
system.collection_min(l) | system.collection_max(l)
--------------------------+--------------------------
1 | 3
> SELECT collection_sum(l), collection_avg(l) FROM t;
system.collection_sum(l) | system.collection_avg(l)
--------------------------+--------------------------
6 | 2
{code}
was:
The new mechanism for building native functions introduced by CASSANDRA-17811 can be used to provide within-collection aggregation functions. We can use that mechanism to add new CQL functions to get:
* The number of items in a collection.
* The max/min items of a collection.
* The sum/avg of the items of a numeric collection.
* The keys or the values of a map.
For example:
{code}
CREATE TABLE k.t (k int PRIMARY KEY, l list<int>, m map<int, int>);
INSERT INTO t(k, l, m) VALUES (0, [1, 2, 3], {1:10, 2:20, 3:30});
> SELECT map_keys(m), map_values(m) FROM t;
system.map_keys(m) | system.map_values(m)
--------------------+----------------------
{1, 2, 3} | [10, 20, 30]
> SELECT collection_count(m), collection_count(l) FROM t;
system.collection_count(m) | system.collection_count(l)
----------------------------+----------------------------
3 | 3
> SELECT collection_min(l), collection_max(l) FROM t;
system.collection_min(l) | system.collection_max(l)
--------------------------+--------------------------
1 | 3
> SELECT collection_sum(l), collection_avg(l) FROM t;
system.collection_sum(l) | system.collection_avg(l)
--------------------------+--------------------------
6 | 2
{code}
> Within collection aggregation functions
> ---------------------------------------
>
> Key: CASSANDRA-18060
> URL: https://issues.apache.org/jira/browse/CASSANDRA-18060
> Project: Cassandra
> Issue Type: New Feature
> Components: CQL/Semantics
> Reporter: Andres de la Peña
> Assignee: Andres de la Peña
> Priority: Normal
>
> The new mechanism for dynamically building native functions introduced by CASSANDRA-17811 can be used to provide within-collection aggregation functions. We can use that mechanism to add new CQL functions to get:
> * The number of items in a collection.
> * The max/min items of a collection.
> * The sum/avg of the items of a numeric collection.
> * The keys or the values of a map.
> For example:
> {code:java}
> CREATE TABLE k.t (k int PRIMARY KEY, l list<int>, m map<int, int>);
> INSERT INTO t(k, l, m) VALUES (0, [1, 2, 3], {1:10, 2:20, 3:30});
> > SELECT map_keys(m), map_values(m) FROM t;
> system.map_keys(m) | system.map_values(m)
> --------------------+----------------------
> {1, 2, 3} | [10, 20, 30]
> > SELECT collection_count(m), collection_count(l) FROM t;
> system.collection_count(m) | system.collection_count(l)
> ----------------------------+----------------------------
> 3 | 3
> > SELECT collection_min(l), collection_max(l) FROM t;
> system.collection_min(l) | system.collection_max(l)
> --------------------------+--------------------------
> 1 | 3
> > SELECT collection_sum(l), collection_avg(l) FROM t;
> system.collection_sum(l) | system.collection_avg(l)
> --------------------------+--------------------------
> 6 | 2
> {code}
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
---------------------------------------------------------------------
To unsubscribe, e-mail: commits-unsubscribe@cassandra.apache.org
For additional commands, e-mail: commits-help@cassandra.apache.org