E.g. like get_count(key) in pycassa.
Or, when will this be implemented in CQL?
Thanks,
Charlie | DBA
Can I get number of columns by rowkey in CQL?
(10 posts) (5 voices)- Started 1 year ago by
- Latest reply from
- This topic is not a support question
-
Anonymous
UnregisteredPosted 1 year ago # -
http://www.datastax.com/docs/1.0/references/cql/SELECT
You should be able to do:
SELECT count(*) FROM <keyspace>.<columnfamily> WHERE KEY = <key>
Posted 1 year ago # -
That's correct, but to elaborate, you would need to define a composite PK on that columnfamily and then use the *partition key* in the WHERE clause. See http://www.datastax.com/dev/blog/schema-in-cassandra-1-1 for an explanation.
Composite PK is only supported in Cassandra 1.1.
Posted 1 year ago # -
Anonymous
UnregisteredHi Jonathan Ellis and Nickmbailey,
Thanks for the reply. I'll try composite PK on Cassandra 1.1 later.
FYI,
It doesn't work on Cassandra 1.0.7. ;)
/home/cassandra>cqlsh
Connected to Test Cluster at localhost:9160.
[cqlsh 2.0.0 | Cassandra 1.0.7 | CQL spec 2.0.0 | Thrift protocol 19.20.0]
Use HELP for help.
cqlsh>
cqlsh> CREATE KEYSPACE demo with strategy_class = 'SimpleStrategy' and strategy_options:replication_factor=1;cqlsh> use demo;
cqlsh:demo> CREATE COLUMNFAMILY c1 (id int PRIMARY KEY)
... WITH comparator=varchar AND default_validation=int;cqlsh:demo> update c1 set a01 =1 where id = 1;
cqlsh:demo> update c1 set a02 =1 where id = 1;
cqlsh:demo> update c1 set a03 =1 where id = 1;
cqlsh:demo> update c1 set a04 =1 where id = 1;
cqlsh:demo> update c1 set a05 =1 where id = 1;
cqlsh:demo> update c1 set a06 =1 where id = 1;
cqlsh:demo> update c1 set a07 =1 where id = 1;
cqlsh:demo> update c1 set a08 =1 where id = 1;
cqlsh:demo> update c1 set a09 =1 where id = 1;
...
cqlsh:demo> update c1 set a25 =1 where id = 1;
cqlsh:demo>
cqlsh:demo>cqlsh:demo> SELECT count(*) FROM demo.c1 where id=1;
count |
1 |Thanks,
Charlie | DBAPosted 1 year ago # -
Anonymous
UnregisteredSure. I'll test it after CQL3.0 is released.
Posted 1 year ago # -
Anonymous
UnregisteredIt didn't work on my local CQL 3.0.
FYI,
$>cqlsh --cql3
Connected to MyCluster at xxx:9160.
[cqlsh 2.2.0 | Cassandra 1.1.0 | CQL spec 3.0.0 | Thrift protocol 19.30.0]
Use HELP for help.
cqlsh> use demo;
cqlsh:demo> SELECT count(*) FROM demo.c1 where id=1;
Bad Request: Only COUNT(*) and COUNT(1) operations are currently supported.cqlsh:demo> SELECT count(1) FROM demo.c1 where id=1;
count
-------
1Thanks,
Charlie | DBAPosted 1 year ago # -
Anonymous
Unregistered[cqlsh 2.2.0 | Cassandra 1.1.0 | CQL spec 3.0.0 | Thrift protocol 19.30.0]
Use HELP for help.cqlsh> use demo;
drop COLUMNFAMILY isbn_price_v3k3;
CREATE COLUMNFAMILY isbn_price_v3k3
(isbn varchar,
price float,
listing_id int,
qty int,
obj varchar,
PRIMARY KEY (isbn, price, listing_id)
);insert into isbn_price_v3k3(isbn, price, listing_id, obj) values ('111222333444',1.2,1001,'axxxxxxxxx');
insert into isbn_price_v3k3(isbn, price, listing_id, obj) values ('111222333444',1.2,1002,'axxxxxxxxx');
insert into isbn_price_v3k3(isbn, price, listing_id, obj) values ('111222333444',1.2,1003,'axxxxxxxxx');
insert into isbn_price_v3k3(isbn, price, listing_id, obj) values ('111222333444',5.5,1004,'axxxxxxxxx');
insert into isbn_price_v3k3(isbn, price, listing_id, obj) values ('111222333444',5.5,1005,'axxxxxxxxx');
insert into isbn_price_v3k3(isbn, price, listing_id, obj) values ('111222333444',1.2, 995,'axxxxxxxxx');
insert into isbn_price_v3k3(isbn, price, listing_id, obj) values ('111222333444',5.5, 978,'bxxxxxxxxx');cqlsh:demo> SELECT isbn, price FROM isbn_price_v3 where isbn='111222333444';
isbn | price
--------------+-------
111222333444 | 2.2
111222333444 | 3.4
111222333444 | 5.5
111222333444 | 7.1
111222333444 | 7.2
111222333444 | 7.3
111222333444 | 9.8cqlsh:demo> SELECT count(*) FROM isbn_price_v3 where isbn='111222333444';
Bad Request: Only COUNT(*) and COUNT(1) operations are currently supported.
cqlsh:demo> SELECT count(1) FROM isbn_price_v3 where isbn='111222333444';
count
-------
1It still didn't work.
Thanks,
Charlie|DBAPosted 1 year ago # -
Confirmed, there's a bug here in the CQL3 parser- it doesn't treat the * right. Use "count(1)" instead for now; it is precisely equivalent. This is fixed in https://issues.apache.org/jira/browse/CASSANDRA-4185 .
Posted 1 year ago # -
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Posted 1 year ago #
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