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Sylvain Lebresne commented on CASSANDRA-10310: ---------------------------------------------- bq. SQL server and Oracle allow you to cast a column and get whatever value you want. Yes, and that's what we should support imo (if for no other reasons than because that's a solution that doesn't break backward compatibility). In fact, that's what I suggested in [my comment|https://issues.apache.org/jira/browse/CASSANDRA-4914?focusedCommentId=14132148&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-14132148] and to be honest I though we supported it, but appears that fell through the cracks. > avg() on int give incorrect results (returning int instead of decimal or > float) > ------------------------------------------------------------------------------- > > Key: CASSANDRA-10310 > URL: https://issues.apache.org/jira/browse/CASSANDRA-10310 > Project: Cassandra > Issue Type: Bug > Reporter: Jon Haddad > Labels: patch > Attachments: cassandra-2.2-10310.txt, cassandra-3.0-10310.txt > > > When selecting an avg() of int values, the type of the avg value returned is > an int as well, meaning it's rounded off to an incorrect answer. This is > both incorrect and inconsistent with other databases. > Example: > {quote} > cqlsh:test> select * from monkey where id = 1; > id | i | v > ----+---+--- > 1 | 1 | 1 > 1 | 2 | 1 > 1 | 3 | 2 > (3 rows) > cqlsh:test> select avg(v) from monkey where id = 1; > system.avg(v) > --------------- > 1 > (1 rows) > {quote} > I tried avg() with MySQL, here's the result: > {quote} > mysql> create table blah ( id int primary key, v int ); > Query OK, 0 rows affected (0.15 sec) > mysql> insert into blah set id = 1, v = 1; > Query OK, 1 row affected (0.02 sec) > mysql> insert into blah set id = 1, v = 1; > ERROR 1062 (23000): Duplicate entry '1' for key 'PRIMARY' > mysql> insert into blah set id = 2, v = 1; > Query OK, 1 row affected (0.01 sec) > mysql> insert into blah set id = 3, v = 2; > Query OK, 1 row affected (0.01 sec) > mysql> select avg(v) from blah; > +--------+ > | avg(v) | > +--------+ > | 1.3333 | > +--------+ > 1 row in set (0.00 sec) > {quote} > I created a new table using the above query. The result: > {quote} > mysql> create table foo as select avg(v) as a from blah; > Query OK, 1 row affected, 1 warning (0.04 sec) > Records: 1 Duplicates: 0 Warnings: 1 > mysql> desc foo; > +-------+---------------+------+-----+---------+-------+ > | Field | Type | Null | Key | Default | Extra | > +-------+---------------+------+-----+---------+-------+ > | a | decimal(14,4) | YES | | NULL | | > +-------+---------------+------+-----+---------+-------+ > 1 row in set (0.01 sec) > {quote} > It works the same way in postgres, and to my knowledge, every RDBMs. > Broken in 2.2, 3.0. -- This message was sent by Atlassian JIRA (v6.3.4#6332)